Belly Time

Ftm here!!My daughter who will be there months on February 12th absolutely hates belly time. She screams, cries, and it takes her breathe away. She barley can hold her head up. Should I call doctor? Is she behind or may be in pain. I was hoping she just hated being on her belly and I continued to practice with her but no improvement. She can hold her head up perfect when I'm holding her straight up but when on belly it's a huge problem.