What Could Cramps In Abdomen And Spotting Signify?

hello I am a 29 year old female who had her last cycle last week which end on the 6 of august. on Saturday or so I started spot bleeding which is also coming out like a gel type everytine I wipe.. have had this issue for about a month now when I have my cycle but at the end. I am very sexually active with my boyfriend. the pregnancy test I took came up negative what could this mean I also am hving some cramping down in that area as well