Toyota Corolla-Loud Soud from compressor

Yesterday my AC stopped blowing out cold air. The fan works fine and the heater still works. Now there is a loud sound coming from the compressor. My car sounds like a Ford 150 now. My guages are fine. Checked the belts and they seem to be fine as well. Someone said something about my bearings or the pulley? Any ideas before I take to shop??? I know replacing the compressor will be very expensive. If it is compressor can I change it out myself?

It may be low on fluid.