Should I sue? What u think?

I'm 19 weeks pregnant, I haven't been working in 4 weeks, I was sent to the ER during my shift April 13th, because I was dealing with sharp pelvic pains which I couldn't continue to perform my job. I work in a hospital btw as a medical assistant/ nurse aid. The work is very demanding. I feel like I have lost my job or something cause on the April 26 I was seen by my obgyn and she said it was ok to return to work. But my employer didn't approved until they sent me a packet in the mail for my doctor to fill out. My doctor was upset when I came back so she can file more paper work. So I'm currently out of work still waiting for an approval to go back. My baby is low in the cervix so I'm not of I should be putting lots of stress in my body. Someone told me I can sue my employer, cause they forced me to leave, which is a red flag. Should I even continue working at this point. I'm not sure when I will return the schudule for the month was probably already made. I'm not getting paid while on leave either. I feel so embarrassed cause they didn't find anything in the ER but I was in a lot of pain. Second time on leave. I feel like I'm wasting time.