Why does my marriage get rocky every time im pregnant?

Is it truly my hormones? I’m currently pregnant with our 4th and last child and my husband and I can’t seem to stop bickering. I’ve noticed that we don’t seem to get along when I’m pregnant. My husband is truly my best friend but lately I want nothing to do with him. It’s really weird and I’m starting to think I’m the problem. When I’m pregnant we bicker over the smallest things. It’s like our communication skills go out the window. I also go from super affectionate to not wanting him near me. I feel sick nauseous most days and really don’t want to be touched. My lack of affection may affect him more than he lets on. I feel so much guilt like why can’t we get along while I’m pregnant? It’s horrible idk what to do. I miss my best friend 😢