Contemplating Nursing School - Please help!

I am planning to apply to the nursing program Sept 1st, and I have a huge concern. I am afraid my criminal background is going to get in the way of me becoming a nurse. 2 1/2 yrs ago I was arrested for posession of cocaine and since then I have been clean and totally turned my life around. The felony was dropped to a misdemeanor because it was my 1st offense and I did all the things I was required to do by the judge.
My background will not get in the way of me getting accepted to the program, but when its time to do my clinicals some of the hospitals may not allow me to work there. I called to program chair at my school today, and she didn't have anything encouraging to say to me at all.
I am so discouraged right now it makes me sick. I have worked so hard to get this far in school. I don't want to give up now. People make mistakes and people do change. 2 1/2 years ago I was living on the streets, my family hadn't seen me in months and they thought they would bury me. I have accomplished more over these past 2 years than I have in my whole life. I love being clean and sober, it feels so great to have a clear mind!
What should I do?