Hiya hun.
Congratulations on the positive test, and am also sorry to hear about your boyfriend. But anyone who would split up with their partner via a social networking site is clearly *not* someone fit to raise a child anyway. You are definitely better off without him.
I know it's nothing to compare to your situation, but I went through a really really awful break-up when I was only slightly younger than yourself. We'd planned to get married and to stay together forever. Engagement rings exchanged and everything. Then I moved halfway across the country to be with him (we'd met in my hometown, but he lived miiiles away) and a few months later we split up. So there I was on my own in a new town with very few friends. And to make things worse we'd got a 1-year lease on our property and neither of us could afford the rent on our own - so I had to stay living with him another 9 months or so!
But it's times like that when you really work out who your friends are and what your priorities in life are. My friends and family were all really supportive, came to visit me, listened to all my ranting, and generally made everything a whole lot easier. (Which was so much more than I deserved, having done that typical thing where everyone else gets ignored when you think yourself so in love that you only want to see that one person!)
And, yes, at times it really felt like my life was all crumbling down then, like I'd never be happy again and I was totally alone. But now I'm in a relationship that makes me happier than I ever imagined I could be, know to really appreciate the friends that are still there for me whenever I need them, and am doing much more with my life than I would have had I remained in that situation.
Things will get better for you.
Wishing you a healthy and happy pregnancy.
Lu x