How did my life end up like this?

I’m 21. I was in college and I was working on myself and I was happy for once I was happy and i know I was still very young but my mom had me at 17 and skated in and out and my dad molested me until I was 9. I raised all of my siblings because I was the oldest and my parents never stepped up and neither did my step parents. I met a guy who I thought was my age but he was actually my mothers age. All I wanted was a baby but later in life of course, I never planned to get married or anything. My plans were actually very simple and “trailer park trashy” but I had the same plan since I was 6. I was going to live by the beach in a baby pink or baby blue trailer with the pink flamingos out front and have a screened in porch. I was gonna have some dogs and cats. I was gonna be a dental hygienist and have two children I adopted and foster some others. My grandma always said God changed things for a reason and I always said “people plan and God laughs”. So I planned and God definitely laughed, I dropped out of college, lost all my friends, wreaked my car, and got pregnant by a man because he asked me to and I was really stupid and did it. I planned a child with someone I had only known a month. He has another girl pregnant who’s younger than me and so I’ve been doing everything alone. And I’m angry and hurt and I don’t even know if I get to be. I don’t even know if my emotions are valid. I start work today and I’m gonna push myself harder than I ever have because I don’t want to be like my parents. I just can’t believe I could be so stupid and let this happen. And the only reason I mentioned the other girl was because she got pregnant on purpose but without his consent and she’s very open about that. She actually told me she was going to kill my child so I won’t allow him anywhere near me anymore because I understand he needs to be there for her but I don’t believe I would ever let someone say that about my child born or not. I’m very hurt and I really don’t know what to do. I’m 18 weeks and 2 days today. I just got a car seat and bottles for the baby they were hand me downs but that’s not a big deal. I’m really stressed out and I don’t know what to do. Do I block him because he’s a shitty person and do everything by myself like I’ve already been doing or do I lower my standards and ask for help? I’d really like an older woman’s perspective that’s not just going to tell me I’m young and to get over it because it’s not easy to just get over this situation.. please try to be kind as well and before anyone says I said anything to the other girl in the situation I never message her or speak on her unless asked I only brought it up because it affects me even if I don’t say anything. She’s really immature and I know when she gets older she’ll have to deal with karma or whatever you believe in. I have always been respectful and nice to her besides once when she said she was going to kill my baby brother who is 7, I did drag her down some stairs for that but she’s left me alone since that night.