Is this normal?

I'll be 3wks tomorrow according to my cycle, is awful heartburn and nausea normal this early? No BFP yet but I definitely don't feel normal. Anything I eat gives me acid reflux even something a simple as yogurt. Slight cramping off and on throughout the days and going on about 3-4 days of constipation. AF not due til the 15th/16th. Could this be it?!