My faucet in my tub actually fell/flew off while I was using the handheld shower. I pushed it back on and it seemed fine. Now there is a terrible leak downstairs when using the shower but fine just running the water out of the faucet. Thinking maybe there is supposed to be a seal in the faucet or something that needs replacing?

My faucet in my tub actually fell/flew off are you saying that the entire faucet came loose? Or do you mean the handle? Is it leaking past the handle or someplace else? Is this a single handle faucet for both hot and cold? Let me know, back to you, Tom