My parents found out I was drinking?

I'm 19 and I was completely sober when I drove home (I took two shots at 5PM and came back at 1AM). However, I didn't eat anything in between so I the alcohol stayed on my breath. I walked in the door and I was dumb to not think, like always, they never go to sleep before I come back and they smelled my breath and smelled alcohol. I explained the situation and my parents are still pissed. What can I do to make them not pissed? It's so difficult to hang out (even without drinking) because I can't stay over at friends' houses AT ALL and can't be out after a certain time (even though I'm 19!) I'm in college, what do they expect? I do things responsibly. I just don't know what to do. What can I do?