patrisalda... it's possible that your symptoms are all related, though allergic reactions and dizziness are not, typically, symptoms we hear of hypothyroidism.
Along with the TSH, your doctor should, also have ordered Free T3 and Free T4, which are the actual thyroid hormones, while TSH is a pituitary hormone. Be sure, when you see the endo, that you get those tested, as they are much more important than TSH.
TSH is volatile and fluctuates, so it's not unusual that it may have gone from 0.5 last year to 8.6 this year; however, 8.6 is too high and you do need further testing.
Also make sure you get tested for thyroid antibodies, Thyroid Peroxidase Antibodies (TPOab) and Thyroglobulin Antibodies (TgAb), to determine whether or not you have Hashimoto's Thyroiditis. You need them both, as they are both markers for Hashimoto's. Some of us have one or the other and some have them both.