Questions after first prostate orgasm

Throwaway for privacy reasons. So all in all, it felt amazing but I'm freaked out because of 3 things: 1) my prostate or something became monstrously, scarily huge and diamond-hard 2) I'm very confused because I ejaculated but I never touched my penis 3) I only used my fingers cuz I'm penniless until payday at the end of the month. So, basically, WHAT THE HELL does YOUR body do when you prostate orgasm? My body really confused and shocked me. Does your prostate or front wall get gigantic and hard? And was it really just my prostate getting that big? Or was it more than that? And do all your muscles down there contract super hard?? I'm still in disbelief that my body could do all those things. And I'm confused because I ejaculated. I read you're not supposed to ejaculate. I didn't stimulate my penis at all. I did my perineum, but I wasn't pulling the penis skin. I was just going for more prostate stimulation. If you have questions on what I did, you can read the story below. Sorry it's so long and… scientifically explicit.

Starting 2 weeks ago, I started seriously trying for prostate orgasm using all the suggestions on the aneros wiki and on these reddits (basically, be very gentle, still, no very vigorous movements, controlled and focused breathing, etc.). My biggest and only variation is I have no tools. Just fingers. At the end of the month on payday, I'm going to buy aneros and nexus revo. But as of now I'm just using my fingers.

Last week I tried two times with my fingers and no-go, probably due to psychological impedance from impatience. Just now, however, I had a very powerful orgasm. Very different from a traditional male orgasm and I'm still repeating it in my head cuz it was such a new and strange experience. So hard to understand. It took me somewhere between 30 and 45 minutes to achieve. I started with my index finger, found my prostate, kept it still and controlled my contractions and breathing. Still in control, I moved my hand behind my leg and used my thumb. I started using my other hand to press down on my perineum. I got really aroused/felt some new sensations and then returned to normal laying flat on back position and resumed but switched to my middle finger this time. I kept pressing my perineum from here on out.

Using my middle finger and on my back with legs splayed, I barely applied any pressure out of fear of injuring my prostate but I was using my middle finger and making very long "come-here" strokes, always keeping my finger pad(?) on the front wall/prostate(fingernail not making contact, not "flicking" myself). As I did that, the entire front wall of my rectum became so freaking hard and swelled like crazy. That's when I really started feeling intense pleasure with each gentle sweep. Pretty quickly, I was having an orgasm that, to me, was all centered on my prostate and it felt fucking crazy. I arched backwards(not coming off the bed like some others), I couldn't keep my eyes open, I couldn't hear anything, I can't even remember what my breathing was like. I don't know how long it lasted. The two biggest things though were that my entire nether-region was contracted like crazy/the front wall was rock-hard and huge. AND I ejaculated. It felt good but was so surprising and new… Is this how it is for others? Do these things happen every time?

Edit: I thought I should add that my penis was completely erect the entire time, even before I inserted my finger, because I haven't jacked off or ejaculated in like 20 days so i was horny and turned on just getting ready for the prostate masturbation(?)