Phone Stalking…My Fault?

So I did something really stupid a little over a month ago and I’m pretty embarrassed to admit it. I slept with an ex-boyfriend that I absolutely do not like. Not only do I not like him, thinking about what I did makes me want to throw up. And the aftermath of it all is just…I feel like it’s all totally my fault. Like I deserve it for doing something so stupid. It’s horrible and I don’t know what to do.
Just some quick background on this ex: we dated for about a year on and off when I was 19 (I’m 26 now) and had a really rocky relationship. He cheated on me but still to this day will never admit it. I also cheated on him once and did admit it. He also became a compulsive liar about anything and everything while we were together. During the end of our relationship he started to get really angry and yell a lot, though he never became violent towards me (though he was a fan of punching walls and doors). When we broke up we kind of remained friends because we were friends with the same people. Then one night he kicked a chair at my head, and missed instead hitting and denting the ceiling, because of some “mixed signals” he said I gave him and since that time our friendship has been strained to say the least. He’d still call every once in a while to invite me to hang out though I’d always turn him down. But we’d basically talk maybe once every six months online for about 5 minutes.

Anyway…I was completely drunk and it had been a while since I had gotten laid. I was coming home from a baseball game on the train and I ran into him. He was looking pretty good (or at least I think he was, my memory is pretty fuzzy) and I remember thinking, “Okay, I could have sex with him. It’d be okay.” Well, I invited him back to my place and I don’t remember much after that at all. I don’t remember kissing and I definitely don’t remember the sex. The only reason I know it happened was that I woke up naked and there was a used condom in my trash can. Thankfully he was gone in the morning though. Needless to say I woke up with a huge hangover and even though I saw that we used a condom and I was on birth control I ran to Walgreens and immediately purchased some Plan B. There was no way in hell I was getting pregnant with this asshole’s kid.
So I thought that was it. I was in the clear. I had done something really regrettable and stupid but it was over now and I could forget about it. But no. That’s when the phone stalking happened.
The day of my hangover he called me around 1:00. I didn’t pick up. He left a message saying he just wanted to make sure I wasn’t too hungover. Okay, that didn’t sound too bad, but I still didn’t want to talk to him. He called again around 4:00. I didn’t pick up. No message this time.
He texted me two days later, a Saturday, around 8:00 at night. He wanted to know what I was doing. At first I wasn’t going to respond. But then I decided to text back, thinking it was the only way to get him to leave me alone. So I texted that I was staying in because I was tired. He texted back something along the lines of how he was going to come over to my place and make me come out. I could tell he was joking but I didn’t respond.
He texted me again the next Thursday night. He wanted me to come out. I didn’t respond because it was already 9:00 and I had work the next day. And I didn’t want to hang out with him.
At this point, I started to worry that he’s thinking we’re getting back together or something. Part of me wanted to tell him flat out that that night was a mistake and I don’t like him and never will. But I’m really scared of him. Our past history makes me nervous around him and the only reason I wasn’t that one time is because I was so drunk I couldn’t think straight.
The next night, Friday, I go out with my friends from work to a loud and crowded bar. I can’t hear my phone in my purse. By the time we leave the bar late at night I check my phone to see if I’ve missed any calls. He has called me 7 times. He’s left 3 messages. At this point my heart started to beat kind of fast. Maybe he saw me in the bar. Maybe the messages are him cursing me out. I deleted the missed calls and decided not check the voicemails.
Saturday I was taking it easy just lounging around my apartment. Doing a bit of cleaning. The phone rang at 3:00, 5:00, 5:30, 6:00, 8:00, 11:00, 11:15, and 12:30 (these are all approximate guesstimates but you get the idea, he did call 8 times). ALL HIM. 2 more voicemails! It got to be that when each time my phone rang I would jump. I’d be afraid to look at the caller ID. It was always him. I didn’t leave my apartment that day because I was afraid he was outside or something just waiting for me. Again, I deleted the calls and decided not to listen to the messages.
On Sunday he called 3 more times and left one more message. Part of me wanted to send him a text saying leave me alone but I didn’t know what that would do, if that would make him angry or what. Since I hadn’t listened to his messages I had no idea what was going on. And I didn’t want to listen to his messages because I was so scared.
Monday came and went without any calls or texts. I was relieved enough that I was able to listen to the voicemails. They were all pretty normal, which creeped me out more than I thought they would. They just said “Hey, it’s me. Just wondering what you’re up to. Call me back.” Or more or less. But the last one was different. He sounded angrier. “I’ve called you at almost every hour of the day. I don’t know what your problem is or when you’re available. Call me.”
Well I knew I couldn’t call him. He gets really angry and intimidating and I was more scared of him now than I ever had been. I mean, this was stalking me. I wanted it to stop. I wanted him to go away. But somehow I felt like it was all my fault because I had made this stupid mistake of letting him back into my life. I had confused him. I brought this on myself. That’s what he’d say. I’m to blame.
The calls and texts have died down a bit now. I haven’t received the crazy amount like I did since that weekend, which is great. But they haven’t ended. The main problem is I know eventually, sometime soon, I’m probably going to see him again. A mutual friend (one of my best friends) is coming home next month (he lives in Korea) and I just know that there will be an occasion where the two of us will wind up in the same room together. I honestly don’t know what to do. I don’t want another chair kicked at my head. I don’t want him yelling at me for it being all my fault. No one deserves to be stalked like that. I’ve been contemplating just sending him a text saying that he really creeped me out with that barrage of calls or something, but I don’t know. I just want it to go away. I want it to have never happened.
I’m sorry this is so long but I just needed to get this out. I need some support or just someone to listen or share a similar story, anything really.