Period mystery!

I have a question that may never be answered but I'm going to put it out there anyways, I'm suppose to be ok my period but I'm spotting only. I've been spotting for 3 days now and nothing has changed. I haven't had sexual activity in 3 weeks so it couldn't be implantation spotting. I did start a camp which causes me to exercise more than I usually do. My period started the day after I started the camp. Could this pairing be BECAUE of my exercising?! Please let me know!