Implantation?

Hi ladies, I've been try for my first baby for five years now and so far I've had no luck whatsoever. I'm currently 10dpo and yesterday when I went to the toilet I had some dark red cm when I wiped, since then it's gotten lighter and lighter. At the moment there is vertually nothing there. As I haven't been pregnant before and am used to incredibly long and heavy periods I'm wondering if this is implantation bleeding or if its just like a precursor to af coming later? Any insight would be greatly appreciated!