First, are you on any sort of medication that might be suppressing your sensations or have you by any chance had a lower back injury or a pinched spinal nerve?

Another question worth asking is whether you've by any chance been riding a bicycle a lot? Or sitting on an upright bike, say, at the gym and riding for long lengths of time? Or even sitting on a stool in a way that puts pressure underneath and behind your male anatomy down there? Urologists have learned that bicyclists who don't use a special seat designed for men complain of the same problem. Turns out it's because sitting upright and putting your body weight on that perineal area puts pressure on the pudendal nerve, which supplies the penis. The pelvic autonomic plexus is also involved.

Men can also get a form of pudendal "neuralgia," which is basically nerve inflammation, that can cause descreased sensations. You've gotten the advice to go see a doctor for good reason. But you really ought to see a urologist, who'll be more informed about that specific area. That's a fairly noticeable symptom, don't you think, and worth a trip to a doctor, even if it's embarrassing? You wouldn't want the problem to get worse or to begin to affect your erectile function.