Implantation bleeding, or...?

This is my first month charting cm, not actively ttc but not trying not to. I'm not doing bbt or opks, just making note of cm and symptoms with the menstrual/fertility tracking calendar. My cycles are not clockwork regular but most always stay within 32-36 days. I only started noting cm 3-1-11. My last period started 2-9-11, and I'm sure I missed ewcm day because I wasn't looking for it. I noticed on 3-5-11 (cd 25), blood tinged cm, just pinkish, and slight pink spotting on toilet paper one or two hours after and then nothing at all since. I have no idea what day I ovulated/if we bd'ed that day - but does the timing of that line up with implantation spotting? I don't want to test yet because today's the earliest day I'd likely start my period (cd 32), and I have a tendency to start peeing on sticks at 28 days every month like I don't know how long my cycles are. I didn't think much of the spotting at the time but now I'm thinking back and second guessing. Opinions?