Am I Pregnant?!!?!?!?!?

Hi all, Im so confused and I know nobody can say for sure but I feel like im going crazy.

I was due on my period a week ago and nothing. Im never ever late, sometimes early but NEVER late. I feel nauseous all the time but I get like that a little a couple of days before i bleed. Iv had cramps and pains but assumed that was also due to period but still nothing. My headaches are bad, backache, fatigue, constant thirst and constantly needing a wee. My appetite is terrible too and Im usually a great eater.

Iv taken 6 pregnancy tests...6!! All negative. Whats going on? Its hard not getting my hopes up :( xx