I can't stop losing weight

I was diagnosed with UC. I had my surgery on april 2, 2026. I was bout 156 ish before initial surgery which they did the j pouch in the process as well. For while, i drop to 140 but gained back to 149. But now im 138. I am worried. Anyone else have this issue? I use to never have problem with gaining weight. But now... no matter what i eat, i cant stop losing