Is there something wrong with my gut?

Sometimes can be caused by gastroparesis. Where the food isnt being properly crushed as you eat. I would talk to your doc to run few tests. Some symptoms are you feel bloated after eating or nausea. Not saying thats it though...but theres treatment. Id get an appointment soon so you can start feeling better💜🤗

Any changes in mood? That would be the most obvious culprit, since your brain and stomach are so closely linked.

Only a doctor would really know. It isn’t normal to lose weight without diet control and exercise.