What happened to my , please help?

I am 19 years old and I am uncut. I have a long foreskin. The other day I was masturbating and the foreskin rolled back. I kept moving my hands over the head (up and down) without moving the foreskin. Now it feels as though my foreskin stretched because when the foreskin is under the glands there is a gap which was NOT their before. Also I can move my foreskin down more. Can you tell me what happened? also can I do it more because masturbating feels even better now lol.