Overwhelmed already

I am 35 weeks pregnant. I have a baby who's turning 1 October 8th and another child who's Turing 6 October 16th. I am overwhelmed as hell already :( I can barley get sleep, my oldest can listen to save his life and has a serious case of sensory processing disorder and to add to the mix I'm having another baby in five weeks. I want to cry :( I don't want another baby but my husband is so excited ... he comes from a family of 14 kids and is ready for his baby. He works long hours leaving me to tend to the kids 90% of the day.

I have dreams and none of them are to be a stay at home mom... I'm finishing my degree soon and I plan on working as soon as I can.

My own mother has been the least supportive person on the planet and constantly tells me how messy my house is or how shity of a mom I am :(

I'm confused, broken and lost and scared as hell to bring another child into this mess.

My husband is supportive and does as much as he can when he is here and he is aware I am unhappy and does every thing he can to try and please me...

Is this just pregnancy or am I going into depression?

I just feel so alone :( please tell me it'll be okay .... or tell me it won't so I can prepare mentally