Was this rape?

Okay, so I think about something that happened years ago and sometimes I feel like it was rape. I want opinions. One night I drank a lot at a guy friends house and he drank too much too, so he got his friend that was there to bring me home. The night was normal and we all just drank together and sat outside on the porch, played a few drinking games, etc. When I was ready to leave I got in the car with the friend of my guy friend and everything seemed normal.. Then all of a sudden he stopped the car on a dark street ( I have no idea where it was.) He asked me to have sex and I said No. He kept trying to talk me into it, he even offered money to have sex with him. I was confused and didn't want to have sex with him. I just wanted to go home and I kept saying no, this went on for about 10 minutes. My phone was dead or I would have just got out of his car and called someone to pick me up. After I kept telling him no, he finally said "get out of my car and walk home or have sex with me" I was so scared Becuase it was pitch black outside and 3 am and I was 25-30 minutes from my house. I had no idea where I was! We had sex and to this day it haunts me. I hate that I did it. When he was done he freaked out saying "OMG I have a wife, I just committed adultery" (didn't even know he had a wife) I felt even worse and hated myself for it, but he basically made me do it. I cut myself after that happened and took it out on myself. Please tell me it wasn't my fault? Keep in mind I was drunk and not thinking clearly and he knew I didn't want to so he threatened me. I know there's gonna be people who say it's my fault but I just needed to get this out. It happened 7 years ago and I just want to get opinions. 
EDIT: He was 14-15 years older than me. I feel so disgusted thinking about it.