I was kind of blackmailed into a blowjob

Ugh. I hate myself for admiring this even but I was looking in this app called "HighThere" or something like that but there was this guy who was messaging me and we were talking and he asks if I wanted to cruise a blunt so I said okay. I told him I wasn't looking to hook up and he said ok and thought it was kind of weird I think. He asked me to bring some of my weed with me so we could smoke from a bong or something so I brought it with. Next thing I know I'm in his car and his dick is out and I never said ANYTHING to make him think that it was ok. I have a boyfriend and I love him so much I would never do anything to hurt him but this guy told me to suck it or he'd drive off the road and I didn't believe him at first and I said no but then he got really dangerous. I ended up doing it and I felt disgusting afterwards I wanted to cry but I feel like I've cheated on my boyfriend and I can't stop crying because I love him so much.