36 weeks and 4 days and I am so over being pregnant

I’m tired of crying it seems as everyone in my house treats me differently because I’m pregnant I’m 20 yrs old and living with my boyfriend under my parents roof. Everytime my family invites my parents to parties they go without inviting me meanwhile I’m stuck at home all day my twin sister hangs out with our friends and family without inviting me either. I just feel so invisible and feel as if I need some time off being home all day everytime I make plans with friends they cancel on me. And to top it all off I’ve caught my boyfriend cheating texting other girls dirty flirting multiple times which my mom knows and thinks it’s no big deal. I am just so sad and have no one by my side but my baby girl.