About 3 years ago I suddenly developed anxiety , nervousness, fast heart rate , palpitations etc for no apparent reason. I had a few other symptoms, blurred vision , hot skin, tired hot eyes, twitchy muscles in legs, cold hands and feet, occasional fever etc and was tested for hyperthyroidism but results were ok I have been tested 4 more times over the years but always ok For the last 3 months I have been suffering more and more symptoms and have been tested yet again but still ok although potassium midly high at 5.6 My symptoms are still anxiety, fast heart rate etc but now I get hives on my face, waking in the night, slight tremble in hands sometimes, face and neck very hot, sometimes throat feels constricted, tingling/electrical sensations, hair is thin I have been 8 stone since I was 18 and still weigh the same at 37 even though I have had 2 children Is it possible the tests they are doing are missing something ? Thank you