Is it plan b or pregnancy?

I took plan be Jan 6 because condom slipped off...on Jan 10 he fingered me but had washed the pre-cum off his finger. On Jan 14 I had brown spotting then the following day had light bleeding for 3 days not enough to fill up a pad. My period was due the 22nd and I had nothing. I took a pregnancy test and it was negative today. I noticed the veins in my body have been showing alot, muscle cramps, sore breast, and a little pinching pain under belly button. Is it possible that I might be pregnant or is it the pill?? And if I got a negative today should i take another one later? Can you get pregnant by fingering if there was precum on finger?....Sorry I know too many questions. Im just confused to what is going on with my body.