I Am Worried

I'm terrified for my future! I'm graduating high school and this will be the first summer i have not had a sport to occupy all of my time. I will be working but that's like every other day. When I'm alone and free, i contemplate my life worth, I think of suicide. I used to cut and I've been getting the urges lately. (Not for attention, only two people ever knew) I decided I should tell my counselor about my worries and my past (I've never told her) but I don't know how to do it, I don't know if I'm strong enough! How should I do it, I'm afraid my life could end this summer or I could relapse and I don't want to, but the urges will take over. I don't know what to do