What Causes A Light Menstrual Period With Nausea And Heartburn?

My period comes every 34 days but for some reason it came 22 days after my last one and i didnt get any cramping (when normally it would be so bad til i would just have to lay in the bed with a heating pad for the day) and it was light redish pink and i didnt see the little pieces of thick blood in it at all. I have really bad heartburn and feel sick off and on throughout the day, plus im always tired and constantly have butterflies. What could this be?