First off, to address the question of what are the symptoms of high TSH levels - there are none, because TSH, itself causes no condition and no symptoms on its own. TSH is a pituitary hormone that's produced to stimulate the thyroid so it will produce thyroid hormones. Just as TSH causes no symptoms on its own, neither does it alleviate any symptoms...
Symptoms or lack thereof come from the lack or adequacy of the active thyroid hormones, Free T4 and Free T3.
In a perfect world, the body produces thyroid hormones "on demand" aka when we need them. During times of stress, we need more thyroid hormones, so it's true that our TSH would rise in order to stimulate the thyroid. If the thyroid does not respond adequately, TSH levels will remain higher for a longer period.
If you could please tell us what thyroid tests you had done and what the results of those test were, it would be a great help. Also, please include reference ranges with any results, since ranges vary from lab to lab so have to come from your own reports.
Since you were tested for "all thyroid diseases", I'll assume you had antibody tests to determine whether you have Hashimoto's, which is the most prevalent cause of hypothyroidism, which appears to be what you have. Please include those antibody results and reference ranges for us, as well.
It's not unusual for one with Hashimoto's to cycle between hypothyroid and normal for many years before settling into permanent hypothyroidism.
You said you an ultrasound "to look for anything on my thyroid or pituitary gland"... an ultrasound won't find pituitary issues; you'd have to have a CT or MRI of the brain to do that - did you have one of those?
6.5 is not all that high considering TSH can go as high as 300, 400 and 500.
AACE has revised/amended version 2006 - page 9.
AACE 2006 (amended version) and the US Government 2004, has set the guidelines for diagnose for Overt Hypothyroidism and Levothyroxine therapy is reasonable with a TSH Higher Than 10.
TSH levels and treatment is also based on different factors and conditions, such as nodule/goiter.
The AACE TSH 0.3-3.0 that everyone keeps referring to, is a target range once diagnosed and on meds. Not a diagnose level. Amended version Page 9.
Many other health condition share the same symptoms of thyroid. So levels determine thyroid conditions.
If you are having stress and its giving you issue, doctor can give you prescription for meds. to help with your situation.
Follow your doctor, not the internet. After all, doctor is the one with the long, expensive education.
Any time you run a low TSH it is a big deal on the body. Thyroid affects every part of your body. The normal ranges set by the AACE are 0.3-3.0. Having a TSH of 115 would be unbelievable. You wouldn't be able to move a muscle, finger, and eyelash. What on earth is she thinking?!
You need to find an endocrinologist who specializes in thyroid or a thyroid specialist.
Physical symptoms are fatigue, constipation, brain fog, muscle weakness, tingly digits, lots and lots of pain everywhere, depression, stress, the list goes on and on. Do a search on hypothyroid symptoms and you should be able to find the complete list.
Good luck and keep us posted.
Dac