Are you suddenly having trouble understanding what other people are saying? Not completely confident it’s entirely on them?
A few things could be going on.
In the “you gotta be kidding me” section there’s the possibility that you’ve just got too much of a good thing going on in your ear. As in earwax, which actually is important as a lubricant and defense against infection for your ears. But too much of it can get in the way of hearing. Don’t go digging it out—this can makes things worse and even cause damage—but rather tilt your head and put 5 to 10 drops of hydrogen peroxide in your ear. Hold there for a couple of minutes and let it start dissolving things.
If your earwax hasn’t been doing its job, then you could be suffering from a mild ear infection. The body will respond to this with inflammation, which can result in the eardrum being impacted.
The bacterial infection known far and wide as swimmer’s ear—brought on by too much moisture in the ear—can lead to the same result, in part because the diameter of the ear canal is reduced due to swelling.
Those are the most common, and least worrisome, causes of sudden “muddy” hearing.
Not surprisingly, a ruptured eardrum can also have a rather drastic and sudden impact on your hearing. Sometimes a bad infection can damage an eardrum this profoundly, but usually you’ll know when it happened—exposure to a loud noise or blow to the head.
Finally, occasionally a tumor—usually benign and known as an acoustic neuroma—can develop that slowly narrows the ear canal until, one day, you notice something’s not quite right. These can be treated with surgery or radiation.
All of the above are issues that usually crop up in only one ear. If there are persistent issues in both ears—especially without any sign of infection—then an immediate visit to a hearing health professional is called for.