What happens if I refuse a field test?

Recently I was pulled over while driving late at night under suspicion of being under the influence of alcohol. I do not drink, however, I do admit that I had a very small amount of marijuana on me and that I smoked a little bit about 45 mins prior (please save me the lecture). The officer pulled me over because he said that I was "swerving and going 15 under" even though this wasn't true. What actually happened was that I was the only car on the road and there was another car about a football field behind me for about 4 miles. Occasionally it would change over into the same lane as me but then right away I would get into the other lane afterwards. I was getting very sketched out but did not yet know it was a cop. Finally we were getting close to the end of the road and I was about to turn at the left turn light, which was green, and then he pulled me over. The officer said I looked "a little off" and became suspicious of alcohol. *See additional details below (not enough characters left)*