Since you stated that you can't figure out what is going on, I take that as you never used to have this issue?
I used to have no bowel issues, then suddenly one day I did not go. This lasted for 30 days, on the 30th day after eating garlic for the huge bloat, I found I had intestinal worms. It's horrible to think about, but if it can happen to me, it can happen to anyone.
Just something to consider. I think anyone who has sudden change in bowels, ruling out more serious disease of course, should consider parasites as a possible cause.