Out of my mind and can’t have another doctor tell me everything is ‘fine’

25f struggling past few years with fatigue, brain fog, cold hands and feet, heat intolerance, anxiety and rapid heart rate (have been diagnosed and take medication for POTS which is relatively controlled now). I have negative celiac screening but had to remove gluten and dairy from my diet. I have extremely heavy periods and take tranexemic acid. My ferritin has never been above 30 despite supplementation lowest documented was 7, B12 is around 200-300 unless supplementing. TSH has increased 0.7 each year from 2024 (1.6, 2.2) and in April was 2.8. I also have consistently low neutrophils if that’s relevant. GP says result of 6 years of vegetarian and heavy periods (stopped in October 25) Please help and offer advice if you can