Finding prostate with hands?

You're arms and fingers just might not be long enough. Also depends on your position it may have been hiding. Condom covered toothbrush handle and go find it.

I don't feel a walnut either. The only time I feel anything obvious and protruding is when I'm ejaculating. If I press a little deeper I can feel rounded areas that may or may not be it. It could be the very base of the penis, I don't know.
I have managed to hit a pleasure spot, but it takes some time to warm up. It's difficult, because you have to be stimulating the right area for a while before you know you're stimulating the right area. And that mirrors my aneros experience, my prostate can feel amazingly responsive, but it has to get there first.
Maybe it'd be a good idea to get your prostate worked up by using the aneros, then go finger-fishing?

I find that my prostate is not responsive when I'm not aroused. When I am, it will swell a bit and is easier to find. After some Aneros play or edging it will respond with pleasure because it is 'ready'.
I like to use a glass dildo that is relatively short in length and curved; It has a sorta ball at the end that is not that big. It requires a certain angle that is difficult to maintain with fingers for me.
A Frog like position while bending forward a bit, tilting the hips back, exposes my prostate the most. Lying down, knees to chest also works for me.
I would advise to take it slow and subtle; easy smooth motions. It sounds logical to use rough motions and start pounding on it to produce more feels, but while that is very nice, I would save that for when you get pleasure out of it and are aroused; try to go for a build up is what I'm suggesting; treat it like it's shy.

Also, that weird feeling you are describing might be it. Without arousal, it feels weird and if you press it with a full bladder you can feel the need to urinate. That might also be a tip: try it with a full bladder. I'm not sure but I feel like it sticks out a bit more because of it.

It can be hard to go from the weird feeling to pleasure. I felt that this took a while for me and might also be part of 'rewiring'.