Tummy time!

Can anyone help with tummy time, my daughter absolutely hates it, she doesn’t even try to lift her head during it just cries until it’s over, i sit and talk to her and use toys but it doesn’t seem to help, I don’t even think she knows I’m there half the time because she just cries with her eyes shut as if in a temper. I’ve been at the doctor twice because i mentioned it at her 6 week check and she seems to have a flat side because she leans to left constant so I’ve been trying to keep her off it, however this is the way she likes her head. She is 13 weeks should i be really concerned? Or should the doctor even? She was a low birth weight baby and a couple weeks early so i consider her a couple weeks younger than what she is as she has only just reached 10lbs. Could she even support her head at that weight? If i have her on my shoulder she will hold her head up but bobs about, the doc is more worried she was using her eyes to follow things instead of actually turning her head to the right to do it, I’ve got a week before I’m back and am getting nowhere it seems 😭 Any tips/suggestions welcome. I don’t want this to become an issue for her. Thanks 😊