No may just be that you are having night time erictions that feel good to you while you sleep.
Have you noticed that there are semen stains on your sheets and clothing when you awake each morning? Do you recognize in your sleep that the semen discharge is pleasant, like a wet dream? During ejaculation, sperm is mixed with other fluids(4 or 5)from other places and glands. Sperm is stored in the epididymis that rests on top of the testicle. The semen leakage could be from any of the fluids that occur during ejaculation. I can remember when my reproduction organs malfunctioned, and I ejaculated pure sperm without the fluids, and it was slightly painful. An urologist is about the only specialist I know that can answer your exact question. The valve in people's bladder can relax and cause urine leakage, so maybe there is something in your plumbing that is leaking. You can call the Urology Department at a medical center where you live and inquire. I would think that any urology staff member could give you advice wheher you need to make an appointment or not. I do not think you have a disease.
Harrald