All Of A Sudden I Started Breaking Out All Over

All of a sudden I started breaking out all over the my chin rapidly around the time I was suppose to get my period. I also broke out with a rash on my neck that is itchy and my dermatologist has diagnosed me with Dermatitis. My period never came and I am now 19 days late. I took a pregnancy test at 5 days late, negative. I took one at 9 days late, negative. Could I have thyroid disease?