I agree that it sounds like a (partial?) obstruction. I would stick to a fluid diet for some days, there are full caloric drinks containing all nutrients needed. Perhaps even carefully try a laxative. Until you have normal BM again.
My first blockage was several months after takedown, it was (partially) resolved in hospital by a contrast agent with a laxative effect. But I had to deal with abdominal pain after eating for some more weaks, finally doing such a liquid only diet.