Weird period/pregnant?

On the pill and take it regularly; start my period on time always. Had my period almost two weeks ago and it was super light and only had brown blood. Had this for days which is very uncommon for me. I was also very nauseous So I took a pregnancy test and it came back negative. This past week I have drink some and ate some sweets. Have been cramping the last couple days and feeling super nauseous with a migraine. Today I noticed that I was spotting and the blood was pinkish. This is not normal and I don’t know what I should do?