Had diarrhea two weeks ago for 3-4-days. five days ago i got antibiotics, finished today, i'm ill again with diarrhea. two weeks i been ill with severe headaches, dizzy, shaky and yellow poop. what could this be? the antibiotics didn't seem to help

Need to examine: It is not feasible to provide a meaningful opinion without additional history, physical examination and may be some tests. Given the history of antibiotic treatment and diarrhea, you may have C diff and that would require a stool test. It would be prudent to see your doctor, or go the emergency room of the nearest hospital. Wish you good health!