High needs - Big baby. So tired I can't think straight

Hi everyone, I have a big boy who's 7 month old (99+ percentile) and he is so demanding, soooo demanding he can't even be "alone" for 1 minute, I'm a stay at home mom, I kind of think about myself as a mostly single mom, my boyfriend works away from home and we can go days without speaking, and when he's here he doesn't help me at all, I have to ask him to play with our son or look after him so I can shower and it's so freaking exhausting... When I'm alone I can't shower until it's 10pm and baby is asleep, most of the time I can't even brush my teeth. Sometimes I think I'm going to have a breakdown. We live in a small town and I don't have any friends, I don't have a car so I'm basically at home all day. I love my baby so much but sometimes I feel like I can't do this anymore. I see moms with 1 or 3 kids looking beautiful and I feel like a failure, how do they manage to do that? I barely exist! well that's it, sorry for the rambling