Down and out

It's the beginning of my tww and I am feeling sad, down, dont even want to do nothing. Went to a reveal party for my sister in law last weekend got in a fight because my fiancé says I hate her.(.I would say more jealous of her) but seems like always fighting over the little stupid stuff. Not sure anymore. Questioning our relationship? Any one go though this? What to do about it? I feel like if I let him go and find someone with no problems he could have the live he wants:(