My question involves labor and employment law for the state of: Florida

I am 19 weeks pregnant, and at my last checkup a couple of days ago the doctor put me on light duty. I'm a CNA at a small facility, and lifting is what we do. I can't lift over 20 pounds, therefore putting me at a "light duty" position. I was told the will not "create" a position for me, nor will they hold my position until I can resume work. She then told me I need to turn in my letter of resignation if I intend on coming back after my child is born. If I resign, I have nothing, no income, no unemployment, no nothing. I worked anywhere between 3 and 6 days a week but even with the hours I worked, I held a part-time status because I chose the higher pay at the time I was hired, thinking I wouldn't need the insurances. I don't know if that matters, but my main question is...don't they have to find me something to do? If they don't, wouldn't they have to lay me off or fire me? By asking my to resign, isn't that kind of "screwing" myself for lack of better words!