I’m leaking a clear fluid during my period.

While I’m on my period I started leaking I thought so I ran to the bathroom and it was just clear. Like my panties were wet. I took my tampon out and there was blood. I thought maybe I was leaking urine but I felt it coming out through my tampon. It’s so hard to explain and I’m 15. Am I the only one who has had this happen? I’m kinda scared.