Question: is gonna an actual word?
Answer: “Gonna” IS defined as a word in the Merriam-Webster dictionary, and, according to them, has been in use since at least 1806. It's a contraction of “going to”, and is more “slang”, or a colloquialism, than proper English, kind of (kinda) like “ain't”, instead of “isn't” (itself a contraction of “is not”).