So my LO is nearly 6 months old, formula fed, and at 12 week's is when i had my first period. It was heavy and lasted 5 days. Since then i haven't had another period, i've taken pregnancy tests and they are all negative. Blood test came back negative also. I'm very confused as my last period was the 27th of February and it's now the 19th of may, and still no signs of an upcoming period. Has anyone every experienced this before?