Prostate getting less sensitive

Lately, I feel like my prostate is less sensitive than before and looking for some advice from others who might have had the same experience. Before I go into detail let me give you some background information.

I'm 29 years old and my first experience with having a finger up my ass was when I was in high school. I had heard that putting a finger in can intensify your orgasms, so I gave it a try and it indeed did. It wasn't something I did regularly, but only sometimes. Then when I was around 22, there would be a few times where I masturbated from the beginning while touching my prostate. One time I had done this, and it made me cum way too fast. The weird thing is, after that point, during sex my prostate was almost too sensitive when I was doing a "humping" motion and made me cum within minutes. So I masturbated again touching my prostate and forced it to take longer and it sort of undid my my over sensitiveness and I could last as long as I normally could. Still kinda weird when I think about it.

Then when I was around 24 I remember my prostate still being sensitive enough for me to lay on my back and finger it up like I would to a female g spot. It felt really good, but I could never have just a prostate orgasm. If I remember correctly though, sometimes after any masturbation involving my prostate, sometimes my prostate would randomly spasm the next day. Not painful, but just annoying.

Then at around 2009 when I was 26, I remember having sex and my orgasm felt like incomplete, like I could keep going. Well the next time I masturbated, my sperm was this brownish red. Apparently I had a cyst in my prostate. I got on some meds and eventually it went away.

Then one other time last year when I was 28, I masturbated with something I probably should have, a semi hard object in my ass, and after cumming I had some brownish red blood again probably from what I was using. Doctor examined, said it was no biggy and took meds again.

I don't know when this began, but now it's harder to stimulate my prostate. The first time, all it took was a finger to speed up my orgasm. Just a finger or touch of the prostate while jacking off could bring me to orgasm in minutes (though sometimes it had the opposite effect and started to make me go limp -- is that normal?) Now a days, it doesn't really speed my orgasms up that much and laying on my back and touching my prostate doesn't really feel special at all. The one way to get my prostate feeling good is if I lay doggystyle and put my thumb in there and press downwards or rub in a circular motion (still haven't achieved a prostate orgasm).

I don't know if it's cuz I've been watching Japanese porn and it's desensitized me, but lately it takes me a long time to cum when I jack off, at least 20 minutes. Before I could easily do it in 10 minutes.

Has anyone got through anything similar with decreased prostate sensitivity? Can "activating" my prostate bring it back to normal?

Thanks