Hi... I seemed to have this problem too when I fell pregnant. Sudddenly I lost most of my friends because I couldn't do the things they wanted... But I found that there were a couple that hung around, I don't see them much now but I talk to them occasionally... I also found that as soon as my son was born, I found a whole new group of friends that were absolutely great, I have no idea where I would be without them... Try hooking up with other young mums in your area, there should be groups or something... If you tell me where you live, I can try and find some information for you about them...
And as for your so called friends that aren't being so nice. Tell them to mind their own business... It may seem hard but it is better in the long run for you and bubs not to have to deal with fake people. True friends will stick around no matter what...