Any ideas?

I am as of right now, 2 days late for AF. No cramping, bleeding, etc. Took a test last night, and a test today, around mid morning. Both negative. However i have been having similar issues right now that i had when i found out i was pregnant with my first. Heartburn, some constipation, and some foods that ive loved until now, just taste bad. I had a mc in october and my cycles arent all that regular, however the last 3 months have been like clockwork. I need some advice.