What to do?

I have been at my current job less than 6 months, granted I came back to this job due to a new director of nursing. So far i have had to work night shift due to the fact it was only shift open at the time. ********. There was another full time day shift when I came back. Plus when 2 spots opened they stated they couldnt take me off nights due to not having any nurse work the floor. I was told that I would be getting days when a spot opened up. Unforuntely that was not the case. After I got hired and started working, I got told about some list for day shift. Which ok I got it. Got put on a list. Now there is enough staff for nights and 2-3 spots open on days.

This is the question: What should I do? ANother nurse which is a friend overheard the director of nursing and another nurse talk about me. Director stated that she wasnt going to keep a day shift open for me due to me going back to school( certificate in medical billing and coding) and because of my knee. Had to 2 scopes on it to tell me I have arthur in my knee. So i wear a knee brace and get along. I told them at the beginning about my knee. Never a secrect. What should I do? Granted when I bought up day shift before I got pulled into the office for them to tell me I was an unhappy nurse. Any advice besides my husband told me to go find another job. thank you