TSH=Thyroid Stimulating Hormone
There are LOTS and LOTS of resources re: thyroid info… this is just ONE of the many. About.com is fairly easy to navigate and will lead you to many of the others. This is my attempt at just getting you the basics.
and now that you know a little about normal TSH levels… here’s an article to explain WHY your dose may be going up when you think it should be going down:
Thyroid Blood Tests: Understanding TSH levels and Blood Test Results