Earliest you've experienced implantation

Janna • Mom to angel twins born sleeping at 18w and a chemical baby. RIP Maven and Macie and Littlefoot.
I'm only 4-5dpo but yesterday I had a weird fluttering in my uterus all day (I know it's not a baby, but I read it could be from increased blood flow down there in preparation for baby) and then this morning when I wiped there was blood but now it's gone. 
Has anyone had implantation at 4-5dpo? How did your pregnancy turn out? Trying not to get my hopes up...