Should i be worried?

This is my first month on the pill... the pamphlet said I’m covered after 7 days. I took my pill on time every day. I let my bf finish in me around the 20th pill. I didn’t get a “period” until the 6th placebo but it was extremely light and brown blood. I took two pregnancy tests and they were both negative. Ive had some cramps and sore boobs but my nipples aren’t darker. Do you think I could be pregnant?