could be, but not likely. I have been on the pill for about 6 years, missed a pill here and there, and never been pregnant. Everyone is different, and anything is possible, BUT my directions on my OrthoTri-cyclen Lo say to take your pill as soon as you remember (which you did) and a back-up method is not needed. Now if you ever miss 2 pills in a row, use a back-up method for sure.
I don't think it's likely that you are pregnant but the chances go up if you just started on the pill. If you have been on the pill for a while I wouldn't worry too much about it.