Tamarashadow,
When you had your surgery, what type of antibiotics did they give you? If you got clomazapine, that is likely what started your problem. I have had something very similar happen to me. I had a bad leg infection from a splinter, and got clomazapine. It can cause ulcerative colitis. I got so constipated, I had a tennis ball size lump. It has resolved itself now, but the doc has me keeping watch for any symptoms that might indicate ulcerative colitis. I hope this reloves very soon for you. I know how painful it can be.
Tracy