No period on the pill?

I am stressed because I am on Lo Loestrin Fe and I usually get a light (2-3 day period) during the end of my pack (the sugar and iron pills). I just finished a pack and I did not have any signs of a period at all. I have had sex recently but we always use a condom and I have been on the pill for 1 1/2 years. Do I have anything to worry about??