I'm not in the area, nor am I as young as you (gulp!) but I am in a similar situation, so just wanted to say "I hear you..."
I lost a lot of a couple of good lesbian friends when I started this relationship with DP (male) 3 years ago and have lost even more (straight and lesbian) when we got pregnant. I think this is typical, and understandable, with any new expecting mama. The issue gets complicated for queer mothers, however, b/c a lot of people think "How can you be bisexual? You have a husband/boyfriend and a baby." It's hard to know how to express those parts of oneself in (or outside of?) the context of family, which is so traditionally structured around a heterosexual nucleus. And, practically speaking, it's a struggle to maintain one's queerness in the face of all the demands of young motherhood.
Having online friends/kindred spirits will help, but I agree that nothing takes the place of IRL friends. I really don't have any in my area right now...all my good friends are far away, so I'm pretty isolated.
I'm sorry I can't be of more practical help -- I wish I was around the corner from you so I could say "Hey, let's meet for coffee!" but I do wish you luck.