Very stuck!!

I’m feeling super stuck in my current situation. Some back story, I’m 19 and I still live with my parents because I can’t afford to move out quite yet. I had to drop out of college after a semester because I have an autoimmune disorder and was constantly so sick (it’s much more manageable now). So my parents had a baby about 10 months ago (there’s an 18 year age gap between the baby and I) and since I was sick and out of school, I agreed to help them with the baby after my mom went back to work. So my dad usually has the summer off from his job so I asked if I could get a job and they said yes so I did and I started last week and I love it so much. But today was only my 6th day of work and they made me take off work today so I could watch the baby even though my dad was home. I refused again and again but then they started guilting me a lot and I felt really bad and my dad kept saying how much our grandma has had to help and he has had to help all the time and he’s tired and has “other stuff to do” so I ended up having to take off of work which I really didn’t want to do. I’m just really stressed. And I’m trying to save every cent I’ve made so I can move out but then they make me feel like I’m abandoning my little sister if I leave. And I adore this baby so much and I don’t want her to feel like I left her. I just feel so stuck. I’m sorry I know this was a long post, I guess I’m just venting.