5 dbp, spotting can I be pregnant?

My period should be here in 5 days,but I noticed yesterday there was a very tiny amount of brownish blood on my panties. This morning as I was using the restroom I noticed there it was again. When I wiped a goey, pinkish kind of discharge was on the toilet paper. 3 months ago I took plan b and I missed my period I took 4 tests that month and they all came back negative. The following moth I got a really light period that lasted 3.5 days I took a test again and it was negative? My boyfriend and I have been ttc since last month. I don't have any symptoms of pregnancy? What can it be?