Ovulation, witches and bloody pregnancy tests.

I'm confused!

I'm 99% sure I ovulated, all the signs were there, cramping, EWCM with pink blood, head aches, all sorts.

That was on 16th March, AF was 5th, so that works out.

I should have AF back now, but nothing.
Got a lot of lotion like CM, unusual for me. I've got pains in my uterus. when I make sudden movements, cough, laugh, walk.. Anything.
Cramping all day on and off, but no AF, nothing?!

Yet a pregnancy test is negative.

Could I have ovulated, sperm fertilised egg and its only just implanting? That would explain pain but negative test.

I'm baffled.