Can’t buy stuff for the baby

My first daughter was born in 2017, I didn’t think I’d get pregnant at all but I did and it ended in a miscarriage it tore me apart and I wanted to kill myself, but I stayed strong for my daughter then I got pregnant again 3 days later I miscarried again. I thought right there and then I wasn’t meant to have another baby since I can get pregnant no problem but losing babies I can somehow do. Well, I didn’t know you are actually really fertile after a miscarriage so we had lots of sex and I ended up pregnant. I’m 20 weeks with my rainbow baby but I’m honestly so scared to buy anything for this baby. It’s a girl blood and ultrasound have showed girl, and I still have a lot of stuff from my daughter but still, I just can’t seem to buy anything.. I have a echo done in a few weeks because I have a heart condition and with having fluid behind her neck they wanna make sure.. I don’t wanna buy something for her and they say she won’t make it because of a heart defect.. I didn’t have any worries with my first daughter but this baby I am since I’ve had nothing but problems.. I get anxiety just talking about baby stuff, talking about her etc I don’t know if this is normal, and I feel bad because I’ve wanted this for a long time and it’s actually happening but I can’t enjoy my pregnancy.. my boyfriend knows I have anxiety too. I have a lot of my daughters things so we have no problem but it’s like car seat, clothes, etc like stuff she really needs..