So I got a definite faint positive at 8DPO, am now 11DPO and have been getting negatives

I’ve had major headaches all day every day for the last 4 days which is not like me, felt exhausted and sick, have also been feeling dizzy.

I have now started spotting (brown) and period is due Monday. Clearly I am out. This month it hurts more than ever because I had that glimmer of hope, was genuinely convinced I was pregnant. Even people on here could see the line and congratulated me! What’s wrong with me 😔