Newborn sleeping troubles.

Since we got home from the hospital my daughter has hated sleeping without a blanket and hates sleeping on her back. And she HATES being swaddled or put in a sleep sack she screams her head off until you get her out of them. She is three weeks old. And I know it’s a no blanket and back is best is what they say to prevent sids so bring a FTM I’m constantly worried. But if you lay her on her back she will gag constantly. Currently putting her on her side and tucking the blanket under her sides so she can’t roll which seems to be working so far. My cousin keeps saying you’re her mom you know what she likes and what’s best for HER. But I’m still so worried about SIDS or suffocation.