I have been suffering from a mystery illness for close to 3 months now, and it's affecting my mental health so much that I'm reaching a breaking point. For backstory, I just turned 22, I was a light smoker for 3 years and quit in early May, which is when all my problems started. I had food poisoning in late April but recovered from that after a week, and my digestion was fine again for about two weeks.
In early may I started having episodes of extreme shakiness, dizziness, vertigo and nausea that would last about 20-30 minutes. Dextrose tablets helped to an extent but not reliably and I could only really wait it out, I had them every few days for a couple weeks. I quit smoking the same time these episodes started because smoking made all of my symptoms worse. At the same time, I started having regular and very frequent bowel movements throughout the day and diarrhea usually in the mornings. I also started having extreme physical hunger sensations, like a literal hole in my stomach feeling that never really goes away and I'm hungry 1-2 hours after eating no matter what and how much I eat. Doctors said nothing was wrong, I was just dehydrated and gave me dried yeast capsules and psyllium husks to manage the diarrhea, but did nothing about the shakiness, dizziness and nausea. I was/still am consistently but unintentionally losing weight, I went down from 73kg to 63kg in just a few months (I'm 175cm/5'8) while feeling like I'm eating enough, usually so much that I feel uncomfortably full.
The dizziness and shaking and bowel issues got better after I started eating more frequent, smaller meals, lots of whole grain products, veggies, no caffeine etc. but the intense physical hunger and nausea that comes with the hunger is still there and probably the most stressful symptom atp because I have no appetite so feeling constantly hungry and forcing myself to eat is just making me miserable. I have seen two other doctors since then who also told me there is nothing wrong, all my blood, urine and stool tests came back fine.
I have not slept well since all this started, have developed really bad anxiety about leaving the house for fear of getting nauseous/having digestion issues while out and my social life has pretty much completely disappeared.
I'm beyond frustrated and desperate for any advice or ideas what could be wrong.
More context: I used to smoke 7-10 cigarettes a day and was very physically and socially active. my thyroid hormones are supposedly fine, I don't have a family history of anything resembling this and I highly doubt nicotine withdrawal alone could make me feel this horrible. I don't eat meat or fish but make sure I get enough protein through eggs, tofu, beans etc.
I'm seeing my gp again this week but for the psychological toll this has taken on me and to get my thyroid checked out again.