I haven't had my period since New Year's Eve and it lasted from Dec-31 - Jan-5 and I also have not had sex either me and my friend at times do oral and we have cuddles naked but no sex. I also have a thyroid problem and take medicine for it but I haven't lately because I have also had the flu and have been taking other medications that im very iffy about mixing with my thyorid medicine I was scheduled to get my period around Jan-31 - Feb 2 and it is now Feb-11 and im very worried. Do perioda change what day they come every year? Am I overacting and being paranoid? Please help