I was on light duty at work for 2 months now comp dr has decided its not work related

I hurt my shoulder at work 2 months ago. The company dr put me on light duty. I had an xray about a week later, did 4 sessions of pt. The dr decided it wasnt working, told me he was gonna set up an mri. I waited and waited. After weeks and weeks he did an ergonomics test and decided i couldnt have hurt myself at work. I am a 100lb woman doin the same job as 200plus lb men. In the last 5 months 5 men hurt their shoulders and werent denied work comp and got their shoulders fixed but i cant. I was put off work and told i cant come back till 100%. I only have a month of fmla left do to my sons chronic illness i have missed time for. will i get fired when fmla runs out?