I just need to vent

I'm 34 weeks pregnant with my third child, my oldest is almost 4! So they are young still and my husbands brother has moved in with us because him his three kids and lady have no where to go, I was cool with it they said they would find a place fast and what not, well #1 they haven't even been looking or saving money to get there own place! #2 I cook and clean after pretty much everyone! Besides the chores my husband usually helps with I do everything else! #3 I'm just the designated baby sitter and just expected to watch the kids no problem because I don't work. If dinner isn't cooked fast enough I'm the bad guy, I don't have enough snacks to feed the kids 24/7 all day! So I need to do better grocery shopping so the kids can get whatever they want whenever they want, rules are obviously different in each household I do not let me kids have snacks before dinner because they will not eat all the food I made, that rule is broken almost everyday now, I don't leave my kids unsupervised for long because they tend to break things so when my husband and I go upstairs the kids are not allowed to go downstairs of course that hasn't been sticking! Their kids go to bed earlier than ours so we have to make sure our kids are completely quite while they try to go to sleep, but they wake up my kids every morning at 6:00 so of course I cannot sleep! I have to accommodate everyone and I'm 100% sick and tired of it! I'm huge! I can't do much picking up around the house, I'm not everyones mom and I hardly ever get a thank you! And of course when I have something to do its always a struggle to get them to watch the kids. I just want a fucking break I seriously cannot wait to go in for my c section and spend that few days in the hospital just so I can get away!!!