To posters who come on to question why vulnerable op asking for advice about future why she did something in past, that she can't change now, give your head a wobble will you? You don't help her, so why do you do it? Pile on more abuse? Or are you a bit stupid? 
Actually, you just don't think before posting, that your words can hurt.
Anyway... OP. You can do this.
Every mother worries they can't. Whether they have support or not.
Everyone going through a breakup has moments of doubt. Whatever the circumstances.
You have more reasons to worry if you'll cope: you're young, two babies close together. Abusive relationship.
But you know what? Look how far you've come! You had further to go to get out of that relationship, and you did. You were dependent on him, scared, physically and emotionally hurt. And you got out. And built a home. With a baby. Whilst pregnant.
You did that. You are stronger than you think.
Now, start making a plan about who can support you. Your family, your friends. Get in touch with your local Home Start team who may have volunteers to help you in first two years. Get in touch with your local Women's Centre for support. Lots of advice on benefits, staying safe.
Ditto pp about Freedom Programme. And if you do it with others, you'll find friends for life there.
It's ok to be worried about the future. But try not to let that fear paralyse you into inaction and stop you speaking to others to plan your future. I think that twat has stolen enough of your life already.
Good luck, you can do this, for you and your children.