Matt,
i'm going to sound like your mother here - and i'm a lot older than you and a mom, so I do these things, unsolicited.... :)
you were not honest with the woman. You gave her "the vibe"? What is this, high school?? Act like an adult - if you want to break up with someone, what's the waiting, hinting and "vibe-ing" for? If you're "planning" to break up with someone, do it fast, clean and clear. Be honest, for pete's sake!
But you weren't, so....
You slept with her, unprotected (so you thought she was still on the pill? Still, if you don't want to father a child *you* must take responsibility for bc.)
and here's the real insult:
you wanted to break up with her but you slept with her *anyway*?!?!
Sure, maybe it's all a lie, and she isn't pregnant. Well, you lied to her, too. Sleeping with her when you knew you were going to break up in a few days is a lie that you cared about her. What do you expect? Play cruelly with someone's emotions and they'll play with yours, my dear.
Or maybe she is pregnant, and is out to get your *potential* money. Welp, these things happen. Now you have a great opportunity to be the grown up you want to be, and do the right thing. If she is pregnant, *even though* you don't know if you're the father...
Help her through the pregnancy if she wants it.
Help her stay clean if she needs it.
Drive her to appointments if she asks.
Pay the child support (sure, ask for a paternity test after the baby is born), regardless of whatever custody ends up working out (and tigresacanela24 is right - you have to pay even if you never get to see the child).
Don't fight for full custody, unless the mother proves herself unfit.
And next time, wear a damn condom! :x
the plain truth is, you did this to yourself. Quit trying to make this about her.
And let this be a lesson to you, no matter what the results are.
You are as responsible as your partner when it comes to bc.
You are responsible for being honest, if you want honesty back.
You have to grow up.