Does my employer have the right to deny schedule adj w/ other coworkers due to being angry w/ me?

I work as a State Tested Nursing Assistant in a Nursing Home. Our company has a "call-off" policy and all are aware that you will be written up if you call off after 3 times, then written up after 2, than 1, then termination follows. So basically you can call off 8 times in one years time before being terminated. I have a recent call of and actually walked in to explain 3 days in advance about an upcoming call off. The Director of Nurses called me on my private phone afterwards and in a very unprofessional manner proceeded to lecture and yell at me regarding my call off, and as I explained how terrible I felt, and how hard I tried to find someone to cover my shift, that I has exhausted all resources, but had to call off for personal reasons, and explained I was fully aware of the reprocussions of being written up. She did not leave it at that. She proceeded to yell that it was my responsibility to cover my shift...the kicker...she explained that if I called off, she would never again grant a schedule request change from me on her desk. That is the part that is unsettling. Im a grown up mature woman and understand that calling off is not a positive act, however, her stipulations for the balance of my employment there seems like retaliation and harrassment. It is not fair. To testy her...I have already this week submitted 4 requests, and she has denied all 4. They are not requests for personal time off...they are schedule adjustments with other employees. A coworker wants New Years Eve weekend off, and want to work my Christmas weekend because I have little kids...she does not and she would simply rather work Christmas and drink on New Years. That is one example of a schedule request that was denied. It was equal pay to equal hours.