I believe I was wrongfully terminated

So a few days ago I was going into the backroom to get my schedule, and I had a dizzy spell. This happened months after I had hit my head on the job. I had gotten better and decided not to file for workers comp, although I did open a claim.

So during this time I wasn't able to check my schedule and apparently while I was gone my manager called my emergency contact and gave her a work clearance form for me to get filled out by a doctor. Now I had a note from the hospital excusing me for two days and during this time I was unable to work. Then apparently I had a shift the day after, the thing is, is that because of having to go to the emergency room I couldn't obtain my schedule. I didn't know I was working that day and frankly I couldn't be working since I didn't have medical clearance. I was effectively given one day to set up a doctor's appointment (which wasn't possible becuase they didn't have any available) before being terminated.

Overall it feels unfair and ridiculous to be fired like this.

I want to keep my job and it feels like my manager is being unreasonable. She has threatened to cut my hours (and has done this to multiple people ) over small infractions instead of using the warning system and also during the first situation where I hit my head, claimed that I didn't hit my head at all and verbally abused me multiple times, lied to me and didn't call me into work despite changing the schedule after I left then blamed me for it.

I want to keep my job with the company so I can at least transfer but I don't know what to do at this point. Any advice would be appreciated.