Hiya Holly.
I'm so sorry that your so-called "friends" have treated you so unkindly since you fell pregnant - definitely not what you need right now! They sound like scum-bags actually and you're well shot of them. But you're so right when you say that the moment you first hold your baby in your arms, none of this will matter...
I was in exactly the same position as you a decade ago - not kidding! I fell pregnant with my son in 2001 when I was 17 and lost most of my friends in the days after I found out. Sadly my relationship with my son's father also ended 5 months after our son was born, and the few remaining friends I had left, drifted away with him. Even my own first cousin ditched me! (That reeeeeeeally hurt). She was (still is) in a relationship with one of my ex's best friends, and so off she went with them. I think she, along with everyone else, decided I wasn't worth the hassle.
It was a horrible time - especially as for all my faults, I know I would never have been so shitty to someone in the same situation. I may not have totally understood what they were going through, but I sure as hell wouldn't have ditched them. My family weren't particularly supportive either - in fact the only person to wish me luck and congratulations on my pregnancy with DS, was my 14 year old little sister. She really showed up all the "grown-ups" there... 
My story does have a happy ending though: I met a great guy, we fell in love and I made new friends (mostly through him, although some through work). My son is a fantastic little dude and I love him to pieces - he just turned 11 last month. And to top it off, my partner and I now have a 15 month old daughter together. Most days I can't stop smiling! 
Now that we're all approaching 30, the majority of my old "friends" have had babies of their own in the last year or two (I guess this is the acceptable age to do it)! Including my cousin!!! Ironically enough, despite their disinterest in the early days, many of them seem to want to meet up or have messaged me on facebook asking for advice - isn't it funny how I'm suddenly worth knowing now?! I have politely declined their invites! 
The only advice I would give you is to carry on with your education and work, so that you've got as many different avenues as possible to meet new people. My friends now are fantastic, but because the majority of them were my DP's first, I always have that nagging doubt that I might get ditched once again, should me and DP ever go our separate ways. I'm fairly sure they wouldn't, but it's always wise not to put all your eggs in one basket! 
You sound like a lovely girl - keep doing what you're doing and you'll be a social butterfly again in the next year or two! Best of luck with everything (apologies for length)! 