Hi sweetie!!!
Just in case you didn't know, I am a Nurse (Registered), and certified as as Sex Education and Women's Health (contraception) Educator. (whew!) As I am employed by a Catholic Organization -owned Clinic, I almost never get to practice any of this.
So... (wiggling in her chair with glee) thanks to you I get to offer some free advice at last.
(I know a lot of this has been covered above, but please let me put my penny in)
You likely have what is called "retrograde ejaculation", your semen is going up into your bladder rather than out. This can be caused by a lot of different things, some are serious. While a prostate disorder is certainly one cause, I didn't see where you mentioned any trouble urinating, like getting up a lot at night to pee, (nocturia) or unable to empty your bladder fully, or having a "weak stream" and dribbling, or even a little incontinence. All of these are known to come with prostate disease. Of course, even if you don't have any of these symptoms, it might still be a prostate problem.
The biggest possibility is your diabetes. Keeping it controlled is so important. High blood sugars can causes all kinds of problems, including this.
The next possiblity is a medicine, of course. Some meds are famous for causing this problem, like some antidepressants, and some hypertension meds, like Cardura. (doxyzosin) It is used for blood pressure and to treat swollen prostates, and can cause retrograde ejaculation because of its effect on the prostate.

There are SIMPLE, painless (more or less) exams and tests your doctor can do the find out what is going on, so PLEASE, PLEASE go see him or her real soon, love!!!!

Kisses,
Wanda R.N.

__________________
"I wondered, am I a lesbian, am I straight, or bisexual? Then I realized that I am just a slut.
So where's MY parade?"

---Margaret Cho