Spotting during my Cycle?

I was googling to try to figure out why I seem to be spotting in the middle of my cycle. I have been experiencing spotting on cycle day 12 to cycle day 15. Its not heavy, or painful. It takes a whole day to even fill part of a regular absorbency pad. The trouble is that I am always worried that its my period starting too early. Prior to this my concerns about ovulation have given way to concerns about my luteal phase. I am going to keep an eye on it. I don't want to borrow trouble before we even start trying, but its just something I noticed (along with the ovulation thing). I will just have to wait and see.