Hey I'm 25 yrs old. Thanks for your comment.
Living like this is hard. I'm doing cbt at the moment. I've only just had my 2nd session. Fingers crossed it helps
Judging from your note, I think your doc is right. Depression or anxiety can drastically impact one's appetite in either direction. Been there, done that.
Depending on your age, you ought to have a colonoscopy to reassure you that you're OK in that department. Or, simply do a fecal occult blood test.
The irony here is that all the worrying you are doing about your health may in fact be endangering your health. Chronic worry is useless. Instead, take reasonable measures to protect your health, such as I described. Then trust your doctors and your body, and focus on living life. Best wishes!