What will most likely happen because of my DWI?

I was stopped on the highway, due to construction work, patiently waiting for the highway to be reopened, the overseeing VA State Trooper at the site approached my stopped car because of my Tint, gauged it and ticketed me for it. I had not had a single drink ( blew .000) however I had smoked "K2", a legal herb i purchased from a store. He sobriety tested me because my eyes were bloodshot and I was supposedly talking funny. He then failed me on my sobriety test based on how much i was shaking. I was shaking because it was in the 30's and I was very nervous. They searched my car and found nothing. He then took me to the hospital and drew my blood, and the results will most likely turn up THC positive. Any advice or predictions are appreciated. Also I am 18 and have no priors.