But, your Thyroid is not a little thing at all.  It has a major bearing on your entire endocrine system.  A bad thyroid can do some really bad things to you.  You should have your thyroid tested with every check up.  I got a "vacation" from work after mine decided to kill me (long battle...I didn't win) and had to have it removed.  I'm still struggling to get a "correct" balance with it.  Keep changing thyroid replacements to find one that my body is happy with.  And, each brand and dose seems to have a different effect on my kidneys and BP.  An overactive thyroid can cause congestive heart failure and other health issues.  An underactive can have a whole bunch of other issues (especially with females).  But, underactive, though making you feel like a slug, is less likely to kill you than overactive.
Ah.....the the beauty of things that are out of your control.....
Joe....when I first saw your thread topic question my first thought 'answer' was....'get your funeral organised'.
I didn't mention that....preferring to wait till you'd got the level down and could crack a smile....