Falling asleep with blanket over head

Serina • 1 👼 baby 3 year old 🌈 Baby on the way ❤️

Didn’t really think twice about it but I’m 11 weeks and I just pulled the blanket over my head and went to sleep. I was just thinking when I woke up, could that hurt the baby because of the amount of oxygen I’m getting? I mean I always wake up in time if I’m hot or it’s getting hard to breathe. Just wondering