17M facing abdominal issues since past 2 years, doctors are not being able to cure it.

17M started facing this issue in june 2024. I have visited multiple doctors but they have not been able to give me diagnosis. I am in so much discomfort. The symptoms that I experience : 1. ) Upper abdominal pain when waking up or after eating, sometimes it pulses, sometimes it is constant. 2.) Cranker sores in my mouth, inner lips and cheeks. They do tend to come and go. 3.) Nausea but never vomitting 4.) Bloating, feel really heavy and inflated in my stomach 5.) Flatulence with a really foul odour 6.) Yellowish Stool also with a foul smell 7.) Loss of Appetite 8.) A cycle of diarrhea and constipation I don't experience bloating and flatulence if I don't eat. These symptoms were always there but I use to ignore them because no doctor was able to help me, they all just gave me some version of domperidone and pantoprazol and make me go on my way. Recently, they have been too bad. I went to another doctor, he gave me a course of antibiotics and other medications which helped me but didn't cure me. I take no regular medication, I eat a vegetarian diet, my blood reports are all well. My abdomen ultrasound from when this problem originally started 2 years ago was also all okay. I am someone who stressed out too much. These symptoms are exacerbated by stress. What do I do to cure myself?