Everywhere I read, it seemed like it has to implant on days 1-3.
So maybe what I felt was not implantation. I felt it on Sunday and the transfer was on Tuesday.
So far, no implantation bleeding and no positive hpt.
In my case, a failed pregnancy could be a disaster because I can only afford the free frozen donor eggs they are giving me and the window could close on that if it takes too long for a bad pregnancy to resolve.
So I really hope it is a good pregnancy or nothing!