The feeling of isolation and not wanting to participate or be in a group of people CAN be from depression which CAN be cause by hypothyroidism. Not always though. Look through that list gimel posted, because it's a very comprehensive list of symptoms caused by a low functioning thyroid. And if you haven't had your thyroid tested yet, talk to your doctor about getting tested for the standard TSH test as well as the free T3 and T4 tests. Also talk to your doctor about depression and it's causes and (if you want) see if you can get a referral to a counselor or psychiatrist.
Have you been diagnosed with a thyroid condition?
I second gimel's request that you post thyroid test results and lab reference ranges, so members can better assess your situation and possibly offer suggestions that might help you.
Have a look through this very comprehensive list of hypo symptoms and I'm sure you will find some that relate. I'm left wondering if you are being treated for hypothyroidism, but it is not yet effective, or what?
http://thyroid.about.com/cs/basics_starthere/a/hypochecklist.htm
If you will please post your thyroid test results and reference ranges, members will be better able to assess the adequacy of your testing and treatment.