then i went to the toilet again and there was still the same colour and the same amount.,..

Need a bit of help....me and my boyfriend dont ever use protection...my last period was on the 25th of july, was a normal period, my next one was meant to be due on the 22nd of August and it didnt come..im now 10days late but this morning i wiped and there was dark brown reddish blood.. then i went to the toilet again and there was still the same colour and the same amount.,.. i took a HPT when i was 4days late and it came back negative but i researched and the internet said it could be too early...can implantation bleeding happen 10days after expected period?