Always worried when baby is sleeping

I am a first time mom, my baby will be 8 weeks old on Tuesday if going by the date they were born, or tomorrow if going by weeks. After 1 miscarriage and 2 chemical pregnancies and multiple failed IUIs we decided to do IVF and here we are she’s perfect. Of course she is fussy doesn’t always sleep, cries if I set her down, but otherwise I am in love with her I’m the happiest I’ve ever been. I believe I struggle with postpartum anxiety. I’m constantly thinking of the worst when it comes to her sleeping. I don’t want to wake up to something awful. I want to wake up because she’s waking me up or I want to wake up and she still be breathing sleeping peacefully. She sleeps in her bassinet right next to me. Firm mattress, no blankets toys, light layers, currently swaddled (not seeing signs of rolling just yet), I place her on her back, our room always has the window open(I run warm), I also breastfeed. I’m trying to prevent all the risks.

She sometimes will have her chin on her shoulder and I’ll adjust it and I’m so scared of asphyxiation because of it . Is that position okay for her? Is that position a risk? How can I fix it?

I’m constantly checking if she’s breathing. Im scared of her not waking up one day I’m so terrified I wait to sleep because I feel the more I’m awake while she’s sleeping I’ll catch if something is wrong. I worked so hard to get her here I don’t want to lose her