Lisinopril and throid

I posted here in early Sept. about my problems with lisinopril. After reading other posts I started doing some google searches. Because a previous HBP medicine caused my thyroid function go down I was switched to Lisinopril. Two years later, my throid levels which had recovered are now going down again. Several posters mentioned suppelmenting with zinc to deal with the cough so many people develop. A "lisinopril zinc" search had several sites that all stated in practically the same words that no research showed a link to zinc and lisinopril but supplementation might be a good idea. (Don't dose yourself with zinc because that can cause things to go out of whack.) I also found an article by Dr. Ron Hoffman about "Drugs That Steal." He reported that ACE-inhibitors caused zinc to be depleted from the body.
Then, I googled "zinc TSH". TSH is the indicator of how your thyroid is working. There I found several articles about how low zinc levels may cause low thyroid symptoms. Ask low-thyroid sufferers how hard it is to get doctors to diagnose and deal with this wide range of symptoms that are often vague.
Now I'm stuck. Is it lisionpril or is it my thyroid? My doctor sees the HBP first and wants to add medications to deal with the first medication's side effects. But then suppose there are more side effects from the next medication. This is a real quality of life issue.