Around 3 months ago I decided to go to a fitness trainer. I've been held back by an issue, what tends to happen is normally when I do something strenuous (it also happens when temperature switches or the air just becomes more humid) I'll start feeling my heart rate become quicker, then my head feels really weird(/dizzy) and I'll then feel sick and have to throw up or at least dry-retch. The doctor did a full blood test, as they thought the
thyroid gland was the issue, which came back fine.