Late period, negative tests.

I was suppose to have my period Jan 8-14. But it didn’t come down. I’ve taken multiple pregnancy test (digital and non digital) but they’ve all come back negative. There was one with a faint line but since the rest were negative I did not pay it no mind. I did spot for one day Jan 31, it was a brownish color and mainly only when I wiped. The whole month of Jan I’ve been feeling sick, breast sore & cramps. I’m suppose to start this months period tomorrow. I’ve made a doctor appoint for Friday so they can check me out. My periods have been pretty accurate for the past 5 months. Anyone had similar experience?