bleeding a week after period?

I finished my period on the 20th had sex that day was feeling like crap pretty much before my period was convinced I was pregnant till my period came as I was having severe cramps which I never get,headaches and backache exactly same as I had with my little girl so was so sure till my period came, today I went to the toilet and wiped and there was blood that's a week after my period surely that can't be implantiom bleeding? I don't know what to think really hoping, since I lost my little girl in march ive being trying to conceive, sorry it's long