I Have Tinnitus For 4 Years Now. I Went To

I have tinnitus for 4 years now. I went to the some Doctors back then, they did a lot test and they found nothing, they could not tell what caused my tinnitus. It has always been louder in my left ear and very deem in my right ear(barely noticeable). But last sunday, it suddenly became louder in my right ears. I don't know why or how. I was wondering if it's possible to lose your hearing completely but still hearing the tinnitus ringing sound? Like, it would be the only thing that you can hear? If it's possible, don't people become insane overtime because of this? I really hope this is not a thing. Because I don't if I would be able to live this. I'm scared.