Could this be implantation or spotting?

Patient: Since Monday night I’ve had brown spotting,not enough to collect on the underwear but enough to see it every time I wipe.I’m on Ortho Micronor birth control pills. I forgot to take the Monday. I usually take it about 6 PM and I noticed the spotting after the 3 hour time frame. I’m not the best with taking my pill but any time I’ve been later or missed one, I’ve never had any breakthrough bleeding.Last time I had sex was Friday night. Before then probably a week and a half to two weeks ago. I took a pregnancy test on Wednesday and it was negative.Could I be pregnant? I read yesterday that if it was implantation bleeding then a pregnancy result wouldn’t be accurate, so that kind of got me concerned again.I have irregular periods when I’m not on birth control but when I do have them they’re never like this. It’s usually about 2 or 3 days of bleeding normal colored blood and then about two days of spotting to finish it off.I’m not sure about other pregnancy symptoms because I seem to always think I’m pregnant when I’m not so I don’t want to misinterpret small things to sway in favor of being pregnant.

Doctor: