I have been on FMLA due to health issues. My FMLA time ends the end of this week however my doctor wants me to take 2 more weeks off. Well I be fired for this? My employer certainly has made it sound that way

I developed pneumonia and the flu which which has compromised my lung function. I was on oxygen for a month-and-a-half and still have to use it at night with the C PAP. My FMLA time ends this Friday on the 17th June 2016 and I'm supposed to be back to work on the 18th of June 2016. My doctor is wanting me to take 2 more weeks off and I know that I'm going to lose my job because the notice from my company states that I have to come back with no restrictions. I also during this time had surgery on my right shoulder due to work injury from a year ago and I I'm still on light duty from this. I just need to know if I have any recourse in this. Thank you.