I hate being a SAHM

As the title says, I can't stand being a SAHM. My daughter is 2. Her father and I live together and are engaged to be married this August. He works full time and is currently working 12 hour days and weekends so we can have some extra money to pay off bills. I stay home right now because I'm going to school full time. I recently got a part time job for weekends/evenings because I just need time away from the house, my daughter, etc. I love my child but I honestly feel like spending all this time with her is making me an awful parent. I lose my patience often, I find her constant whining infuriating. Some days I want to just lock myself in my bedroom and cry. Shes a good child, doesn't have many behavioral issues other than normal 2 yo things. Dont get me wrong, we have our good days. It just seems like we've been having a lot of bad days lately. Sometimes I feel like I'm failing her 😥 I know many people would love to be able to stay at home, but it's just not for me. I want another child eventually but I know I wont be staying home with him/her. Just needed to vent.