Have Anemia. Took Medicine. Feeling Breathlessness, Weakness And Flu Like Symptoms. Any Ideas?

Question: I have really bizarre random symptoms that neither doctors nor I can work out. This has been going on for 7 months. It began with feeling extremely weak one day. My instinct was to eat something sugary as I felt so bad I thought I had diabetes (I don't have been tested) I went for a blood test and doc said I had anaemia with a ferritin on 4. I started iron tablets. I went from bad to worse, with intermittent feelings of severe dizziness, breathlessness, weakness and generally feeling ill. I also couldn't eat *anything* without having a severe "attack". The attack would cause severe shortness of breath, extreme weakness, feelings of being hot and cold. My legs would also be very painful and all of this was relieved after a bowel movement. It got so bad I was scared to eat and had hypokalemia. An endoscopy was done and showed moderate gastritis but nothing else. I went on PPI's and could finally eat. I was doing well for a while and then I think I started to develop a lot of food intolerances because of the ppi's and also my calcium was slightly low so I have stopped taking them after being on them for 6 months. The severity of my symptoms has improved but I am still getting days when I am extremely ill. Sometimes it feels like flu symptoms i.e.. body aches, runny nose, nausea, generally feeling ill! (had hiv test, negative). I think but can't be sure that it is food related. I have had a brain mri, a small bowel mri and many other tests and everything comes back normal. The only things I have been diagnosed with are gastritis, thyroiditis and allergic conjunctivitis. There are days when I also get severe sinusitis. I have stopped taking levothyroxine that I have taken for over a year incase it was that? I am totally baffled by whatever this is. I can sometimes have days when I feel so well I think I am over it and then it can hit me out of nowhere. There have been very occasional times when I have been too weak to move. Docs have ruled out Addisons. Any ideas? Thanks