please help

the green check marks are when I had sex (I am on the pill no condom) i have slight cramps and have felt off the past two days .. i took a pregnancy test at 8 pm last night and it was negative .. period not for another 2 weeks exactly .. is there anyway I could be pregnant? I am a perfect pill user and had a normal 4/5 day “period” where the pink circles are .. it was on time like it is every month