Retaliation in Iowa by my employer if I file for partial unemployment benefits?

I was hired by a doctor's office as part-time 3 years ago. I then became full-time after a full-time employee quit. Eventually I was made salaried full-time (40 hour week). Another part-time person was hired and has since quit. Instead of hiring another part time person, a full-time person was hired and my hours were cut from 40 to 16. My bosses said they couldn't cut the new-hires hours because she was hired as full-time while I was originally hired as part time. Now, yesterday, the other full-time person I have worked with for years gave her 2-week notice. I was sure that they would give me my full-time hours back. I discovered today (they don't realize that I am aware of this) that they have had a hiring agency post a job opening for another full-time person, so have no intention of giving me my hours back. I'm afraid if I file for partial unemployment I will be fired. In which case, I would apply for full benefits. But I do not want to have my resume reflect that I was fired. Incidentally, I am the oldest person in the office and am being replaced by younger people.