What Could Cause Swollen Tonsils, Frequent Mouth Ulcers, Constant Fatigue, Headaches, Forgetfulness, And Past Nosebleeds?

Hi, so I’ve been to at least 4 doctors now with no proper diagnosis. My tonsils have been swollen for months now to the point I am having trouble breathing and it’s not infected or anything ( I’ve had tests done). I have painful mouth ulcer that come and go. I’ve had at least 12 in the last 4 months in different spots of my mouth. I am also really tired all the time and I experience frequent headaches. Just recently I have developed a bit of forgetfulness. I’ve never been this forgetful before. Sometimes I won’t remember what I was going to say or do , it will either take up to 30 minutes for me to remember or I just never remember it at all . It’s really frustrating because I am a college student. I don’t know if this is as relevant but I used to get really bad nose bleeds. My nose would bleed in my sleep or while I’m trying to eat. Sometimes it bleeds for almost an hour heavily but I used some nasal sprays and it helped. Additionally, I have gotten a CT scan done of my neck and brain but nothing came up. I have gotten my thyroid checked and nothing came up. It’s just really frustrating because I don’t feel well.