It’s more than likely your prostate. I had the same issue. My doctor said that my enlarged prostate was what caused me to have to strain to urinate and what was reducing my once healthy and cannon-like ejaculation. :)
You might want to see your doctor and have him order a test or give you the finger test (!) to check your prostate. I used to shoot massive loads, I’m talking Peter North and then some when I’d go 3 days or so without release/masturbation and edged for a few hours before finally letting go. Then one day it was as if I woke up that morning and everything changed. I was only averaging maybe 3 or 4 “shots” of semen and could only launch it half a foot or so on a good day. Before that I could cover 3ft or so.
Of course, age had a little to do with it (I was about 30) and it’s natural to slow down a little bit but not to the point of struggling to eek out a few dribbles.