good luck milkshake. you don't have it easy. i am sensing that your girlfriend's pregnancy triggers depression and that she has unresolved feelings about her ex. the guy probably belongs in jail where he can dry out from heroin and not kill himself. but you wont be able to tell that to her.
if she cant forgive you for reading her journal after what you have been through then she's very tough. that doesn't mean you two can't resolve your differences.
how old is her child now? i mean is it a consideration in your relationship with her?
stay strong!
pi