Having recently just been through my inital with good results for my hearing (probably due to the earplugs) I can see how you can easily fail and have your hearing misdiagnosed. I had to hold my breath at times because that, ontop of my heart beating and slight tinitus in my right ear was all I could hear - difficult to make out a sound in that, I heard the sound clicked the button then wondered if I'd actually heard anything. It's a very dodgy test and I do not feel the sound proof box along with enclosed headphones is the best way of doing it.
I too have slight tinitus, it's something that happens to any musician or music lover over time but rest assure it will eventually go away. Don't give up playing your music, I still do studio and live work with moulded ear plugs and that filters out a lot of the SPL's.