I just can’t deal with it

I live with my partners brother an his girlfriend all of 8 months while me an my partner have been together 3years an 3 months, hey just found out they are pregnant, she smokes, drinks a shit load of coffee an Coca-Cola, she’s super skinny! An it aggravates me because I don’t do any of that an we have been trying for over 2 years. It’s so hard cause I live with them an whenever they bring up anything to do with a baby it hurts me so bad! I also have two best friends, ones pregnant with a boy and the other just found out she’s having a girl! I’m so happy for them and it’s awesome news but it breaks my heart.. I’m isolating myself cause I just don’t really want to hear about babies.. I feel terrible.