I took a mucinex dm pill for the past three days every 12 hours but today as I was using the restroom sitting down, I suddenly felt my ear do this weird like close up. I immediately afterward I felt a distinct dizzy side turn over and over for five minutes even when I closed my eyes, What is wrong with me?

The medicine is probably too strong for you. Or at least your symptoms right now. I took that a few months ago and it made me light headed and extremely tired so I had to stop taking it.