I need help.

This whole life situation is crazy. I work from home, I live with my boyfriend and his family, they are currently fostering 3 of his cousins, and I take care of the 11 month old baby. I have her for 10 hour a day 5 days a week and I feel like it’s becoming too much. Not too much to take care of her but I’m mentally exhausted, I never leave the house, I feel like I’m this child’s mother. I find myself getting irritated and angry really easily. This is totally abnormal for me, I’ve always wanted to have children, I love kids, I worked at a daycare for a long time, but this baby honestly makes me not even want to have children. I feel like the family is In a way taking advantage of me, I feel like I take care of her way more than anyone else and that’s not what I signed up for, I’m at such a loss and it gets worse every day. I’m depressed and upset all the time. I’m scared this will start effecting my relationship.