I need advice about pregnancy and jealousy

Hello, I'm Max I'm 19 and the last several months I've had some complicated feelings about pregnancy. I have spent my whole life raising my siblings as my own children. I would stay up all night to feed and change them. I taught them to read and write. I did the whole teething thing and my kids are in middle and high school now. I had plans to legally adopt them when I turned 18 and get guardianship of them. However, my uncle gained guardianship and he can provide my kids with more than I ever could. I no longer live with my kids, but they will always be my kids and I am still the one that gets call anytime there's an issue. I am in college now pursuing my degree in music education. I finished my freshman year, but I am pursuing my masters degree so I still have four more years of school. I have a very deep desire to get pregnant. Even though I already have kids, I want to birth my own kids. This is always been something I wanted however, I'm very conflicted about birthing my own children. I have several disabilities, and I am not sure if it would be healthy for me to carry a pregnancy or if it would be ethical for me to even have kids biologically. I keep seeing the people I graduated with having children and it makes me upset. I have very complicated feelings because I want to be pregnant so badly but I do not want to put my children through with my mother put me through. Even if it is ethical for me to have children, I need to wait until I graduated school. I can barely afford to take care of myself, let alone a child. I've been having these complicated feelings for a very long right now. I started to feel anxious and upset every time I saw someone pregnant, even if it wasn't even real like on a tv show. I'm in a polyamorous relationship I have a fiancé (male) and a boyfriend and girlfriend. Recently my boyfriend got my girlfriend pregnant. I have not been handling it well. Any small mention of the pregnancy makes me unreasonably upset. I want a chance to be a kid before I have kids I want a chance to take care of myself before my kids. I don't even want kids until I finish school. But it makes me so upset and I don't know what to do. Any advice would be greatly appreciated