Need to Vent

This may be a little long but bare with me. I don’t know if I’m writing this to vent or for a pep talk. I am absolutely exhausted. My 1 year old is either going thru a sleep regression or getting a new tooth but either way the last 2 weeks she’s been sleeping worse then she did as a newborn. Yesterday she woke up with a cold that’s only making things worse. The night before last she was up every 40 mins thru the night. I don’t believe in co-sleeping but if I didn’t take her in with me then I’d be up all night. Last night she didn’t fall asleep until 2 am and was up again at 7. No matter what I tried she wouldn’t lay down. Before all of this she was sleeping 10-12 hours straight. I feel like I’m cracking up from lack of sleep. My husband works until 4 in the morning so naturally he spends most of the morning sleeping so he can’t help much at the moment. I’d send her to my aunts for a night so I can catch up on a little sleep but I don’t want to do that with her not feeling well. On top of that my stepdaughters will be here tonight and tomorrow night. The 6 year old constantly needs to be the centre of attention (she was like this before the baby) and is becoming more and more disobedient. She doesn’t care if she gets in trouble because all eyes are still on her. She follows my daughter around constantly and is constantly in her face and pulling on her..screaming in her face etc. if her older sister is speaking to us she speaks right over her or acts out so the attention will turn to her. (and yes we do everything we’re supposed to. We give her one on one time) It ends up with my husband and I arguing because we’re both so on edge with the 6 year old’s behaviour. I know I’m a terrible person but I’ve come to dread the days she’s here. Any advice?