What Causes Delay In Periods And Negative Pregnancy Test?

Hi, I am Jude. I have been on Alyacen 1/35 for 3 months now. I know in the first few months the cycle needs time to become regular. I had a bit of a scare last time because my boyfriend came home from the military, and after he left I had an extremely light period and only two days, very light. I took a pregnancy test just to be safe, and it was negative, I would also like to say that I am very routine in my pill. Everyday at 7:15 in the morning. Here we are a full. Month after he has left, and it is Thursday of my period week. It has not happened yet. I have had some bleeding last week. But not now. Should I be concerned?