confused?! 😫

So My periods 2 weeks late I've had all the nausea, dizziness, light headedness, I've took 3 hpt all negative I was supposed to start on the 1st, then yesterday I had some cm that was clear and had some stringy blood then today clear cm with a bit more blood I thought I started my period so I put a tampon in I was curious if I bled anymore an hour later and took it back out no blood  it was just a light brown color. I'm having mild cramping but when my period comes it doesn't spot it's just full blown blood and the pain has me doubled over! And it's always in time. So any advice will be greatly appreciated!!!!