I feel like a piece of crap

My husband and I fight so much. All day everyday. He’s done so much to me and I resent him for it all but I’m here because he provides for our kids. And he knows that. I started school a few weeks ago to be a paramedic. So I’m setting myself and daughters up to leave soon. We have a 2.5 year old and a 6 months old. I’m a stay at home mom so I’m always with the kids. I don’t get much help from him and he likes to fight about everything. I potty trained our 2.5 year old. She got good about telling us when She has to go to the bathroom then a few weeks ago she started consistently going on herself. She wouldn’t tell us at all. The only time she would go in the toilet is if we put her on to go. I was googling why that happens and some answers said “stress”. I feel like a piece of crap because we yell at Eachother in front of her. And I think it’s affecting her. Is she just regressing like a normal child would?