I was suppose to get my period on the 13th, it is now the 16 and I have not gotten it. I had acne start 3 days ago then stop. I have been having backaches, and started getting headaches today. We have been TTC for 5 months. I had very slight cramping for two days and today nothing. I took a test this morning (even though I knew it was still pretty early to tell) it came back negative. When is the next time I should take a test?