I am virtually deaf in my right ear following something similar. I had a lot of wax in my ear and went swimming on holiday. The water blocked my ear, and I spent all week trying to unblock it with my finger. This increased the pressure on my ear drum, and my hearing deteriorated rapidly of the next few months after I'd had the wax removed.
Fortunately, my left ear is pretty good.
I'd get it checked out ASAP, as could be something 'fixable' at an early stage.
Cheers,
Rick