I feel like a horrible mom.

I got with an abusive man at the age of 17 while he was 27. I got pregnant at the age of 18 and had my first, pregnant again a few years later and now have 3 kids. I finally left the abusive marriage and now a single mom while he has nothing to do with the kids. I'm struggling. I never really wanted kids and now I'm stuck raising 3 of them. I love them, but I don't feel like the best mom for them. I wanted to travel and get settled in my life before the thought of a family. I'm struggling everyday. I see all these parents taking their kids places and having fun. Meanwhile I'm working all the time, stressed out, and have no money to do anything with the kids. I wish I would've been smarter and left him before I even got pregnant. I want to be able to just pick up and go wherever I want and I can't do that. I want freedom and I really hate myself for saying or thinking like this.