Weak orgasms, lack of that throbbing or pumping sensation prior to ejaculation and a less forceful ejaculation and less semen are typically associated with advancing age but you are way too young to be experiencing orgasm sensation loss!
I recommend your urologist order a total Testosterone blood workup. Total T, Free T, SHBG, LH, DHT, Prolactin, DHEA, TSH (High Sensitive) and, Estradiol. Estradiol is a predominant female hormone that if men do not have enough, or have to much, of will negatively affect their libido.
Problem is, your typical everyday doctor, even urologist, will not recognize subtleties among these tests. You would need to seek the help of a doctor specilizing in male hormones. Anti-aging doctors do this as do some better known like Dr. Shippen who is mentioned frequently in the Men's Health section here.
If you can't get access to a hormone specialist but can afford it (or have a FLEX account) you can order tests online, go to a local lab, and the results are emailed to you.
One thing you *can* do for yourself for free is to start, if you have not already done so, PC muscle exercises. It takes a lot of time to see any results and they must be continued frequently but your PC muscles are directly related to that pumping sensation, the male orgasm, just prior to your ejaculation. It is against board rules here to give step-by-step instruction but you should not have much trouble finding it.