I got my period on 24thjuly till today my period has not come I took a pregnsncy test today it's negative. I am ttc what could be the reason?

Time and Technique. You may tested too early. See this site to see if you have any symptoms of pregnancy, if you do , you may wish to repeat the test in a couple of days. There are many causes of missed period, other than pregnancy, anovulatory cycle being one reason. http://www.webmd.com/baby/guide/pregnancy-am-i-pregnant.