hey ladiws i needs yall help!!!! This started happening yesterday and yes i've had plenty of unprotected sex... what does it mean???

My calander for my period

for the period being late i took a pregnancy test i believe monday and it was negative

Right now I feel dizzy the feeling to throw up and lower back pain.

Update****

I'm currently in the er the dizzyness has not

gotten better nd im running a fever and my muscles feel weak.