Spotting for 6 days, NO full period

Kaitlin

Okay so I was due for my period on December 31st and since January 3rd I have been having dark brown spotting and some red spotting when I wipe but no full period. Normally I will get this one to two days before my full period starts but this month nothing. All pregnancy tests came back negative. Could this just be a weird cycle? My boobs hurt really bad too?