Spotting a week before period and is on birth control.?

I've been freaking out because I'm noticing a faint brown discharge on mu panties. I've been spotting for like 4 days, but it isn't much, it's just a light stain. I am using Cyclessa birth control and only recently started. This would be my third month of using cyclessa, and I took the first inactive pill yesterday. My boyfriend and I did have unprotected sex, he was only in me for a little bit before I made him use a condom. During around the second week of the pack, I took a pill around 2-3 hours late. would that have anything to do with it? or is my body just adjusting to the pills? i've never experienced any type of spotting during the first two months when i started. could i be pregnant?