Well, I'm still pregnant, so I can't say much about managing, but I think maybe you should get in touch with your Community Welfare Office? (That's what it's called in Ireland, anyway). You should be entitled to all sorts of things. Here, pregnant girls get a grant of a couple of hundred to get them started before the baby's born for clothes, pram, cot, etc. After that of course there's child benefit, and there's something here too called Lone Parents' Benefit. Because my boyfriend and I aren't married, I'm entitled to that. There's something called a Rent Allowance too, where a certain percentage of your rent is paid by the Community Welfare.
I don't know how much of that applies to you, but you should definitly check it out. One thing to remember about benefits and that, is to ask about EVERYTHING. Don't wait for them to tell you, because they will leave things out.
As for your family... The whole thing when you were 13 won't exactly help towards the situation, but in the end, it's your life and your baby. Abortion isn't an option for you as you said (and I congratulate you on being so brave with regards to that), so either way you're having a baby. They'll have to deal with it, but they are your family and I'm sure they will come around. Maybe your Mom might even be excited about being a grandparent

I wouldn't tell them right away, if you are though. Maybe wait until the 3 month mark and you're kinda sure everything's healthy, y'know?
Last but not least... I STRONGLY reccomend that you stop the birth control right now until you know wether or not you're pregnant. It can do a lot of damage to your baby of you keep taking it, so lay off it until at least 2 more tests and consider not having sex at least 'till your sure. It's much better to be safe than sorry where your child might be concerned
I hope this helps in some way, and I really wish you the best of luck.