I am 21 yrs of age, unmarried.never had ..the problem is whn i am sleeping i get ejaculation..?

when i am sleeping i get ejaculation...this is happeing frm the past 4 yrs..i dont even get bad dreams but still it happens..this happens 5 to 6 times in a month and i am fed up...hope it doesnt affect my married life..and i feel very much embarressed whnever i sleep in some other persons home.....please help me to find some solution..is their any medication for that one???