help :/

I wanted to ask you girls for some help! Yesterday (day 18) I started to experience some light period pains followed by a mixture of what looks like old and new blood of which some is quite stringy (sorry for tmi) now spotting red graduall through the day, Does this sound like it could be an implantation bleed?? I am still experiencing this day. My cycle is usually 29 days so very early for a period. And not only that but havnt DTD since day before last AF I'm feeling very tired.. too HELP!