I'm still spotting @ 17 dpo! I bled for less than 12 hrs on 6/18/2011!?

Now I'm spotting on/off and some days the spotting doesn't even make it onto my panties (sometimes it's only when I wipe or I actually check my cervical mucous)! Pink CM @ 13 dpo and lite/dark brown spotting since what I thought was AF. Extreme nausea on the 19th when I woke up but it went away shortly after I woke up and now it's on/off. No tender breasts but they really randomly hurt ever so slightly around the outside! I've got a 28-32 day cycle and my actual period should've already come. I don't even have major cramping like I always do right before AF and the day or two following the start of AF (I only used I regular tampon and used a heavy flow for night which is what I normally do but there was barely anything on it the next morning!). Was this AF or implantation spotting?!?! A friend of mine had one day of spotting 14 dpo so I'm hopeful!