Lithium killed my thyroid. I was kind of expecting it to, both my mom and sis have thyroid problems so I was on the lookout.
I got REALLLY unusually tired. Like couldn't do ANYTHING tired. I was cold all the time. I don't think I gained weight but I didn't change any of my habits life just SUUUCKKKKED.
If you are worried (and I doubt sincerely it's either the smoking or the vaping, switching to vaping did not change my--well, actually that's not true. They went up. I also started a different natural thyroid hormone (I am not talking those cheesy supplements they do NOT work, as far as I'm concerned) if anything it's probably AGE or whatever.
But, nothing can tell you if it's a thyroid issue other than blood tests so get thee to thy physician, who can run a test to see.
Also, thyroid is easily treated, but it's a PITA. You "FEEL" the difference in the thyroid hormone but it only SHOWS UP in your lab work like 8 weeks later. So be prepared to, IDK. suffer a bit as you go up as docs are really freaky these days as too much thyroid is REALLY bad.
I have been suppressed (meaning my thyroid is artificially too low) for years but my doc (who had thyroid cancer she is hard to argue with) really wants to get me in a "safe" zone where it's like, once a week (it's today) it's like "Torture Anna day have her take less thyroid" and then at some point like 8 weeks from now they test me and see if it has improved.
Really sort of sucks, but like, once you get it right it's easy. So I hear.
Anna