I Have Been Reading About IBS And Trying To Figure

I have been reading about IBS and trying to figure out if that is what I have. I do have the constipation and bloating, but the question regarding "relief after a bowel movement" is absolutely not true with me. It is AFTER a bowel movement that the bloating and pain begins and lasts all day until I go to sleep for the night and then it is gone in the morning. My question is: why do I feel so bad AFTER a bowel movement?