Can you be immune to Novocaine?

Today I was supposed to get two cavities filled, and was given two shots of what I ume was Novocaine. Thirty minutes after the shots, and I was only slightly numb on one side, and not numb at all on the other side. To make a long and ugly story short, I was given another shot on both sides of my mouth (top jaw, in the back) but they had no effect whatsoever. They attempted to drill one of my teeth, but the pain was too much to handle, so they gave me a temporary filling and let me go. Now I'm wondering if I'm immune to Novocaine and will have to undergo all of this again in the near future.