My last period was november 19 - 24

My fertile day (according to glow) : Nov 29 - Dec 5

*My next period is supposed to be due: Dec 18*

Today is Dec 10 and I'm having cramps and spotting like brown and pink and I saw even a bit of blood.

I get weird cramps, and also when I lift heavy things.

(i write this because I'm scared and don't know very much about it)

Could it be my period?

My friends tell me it can not be my period.