You definitely won't be alone! My girlfriend and I drove out by ourselves last year and within an hour of setting up our tent we were drinking and chatting it up with our tent neighbors on either side. By the next morning we had all moved our tents into a circle and we all hung out the whole weekend. Plus, Americans love a good Irish accent, you'll make friends instantly with anyone!
I spent Saturday by myself last year waiting for friends to arrive on Sunday and I had a lot of fun. I met at least 10 people throughout the day to bullshit with while waiting for bands to come on, drink with on camp ground walks and take shots with during deadmau5. You shouldn't have a problem having a kick ass time.