@proudmomma,
You need counseling. Postpartum depression is very real and can be rather serious (as in, some women can become suicidal). If he will occasionally go with you, that's great, as he sounds like he's got at least self-esteem issues, and may be depressed as well (or maybe he's just a sexist, uncaring jerk, just like his pals seem to be). If not, that's okay, too.
But you need friends, to sometimes help you with your daughter and also to get you talking. You need to find your self-worth in all of this.
PS You'll likely have at least joint custody of your daughter if it goes that way. Maybe even more - I get the feeling he'll have issues with proving he's a responsible parent to most judges. But try counseling at least a little before you go down that road, if you do. Partly because I think you need it anyway, but also because if it goes that way, you'll be glad that you made an effort, even if the effort ended up being for naught.