Quedtionable Pregnancy

I have infertility issues, BUT, ive taken estrogen for my period to start and Clomid for the second time 12/15/13 and clomid on the 3rd day of my period 12/26/13. I was supposed to get my period yesturday 1/20/14, and i never got it. My stomach is always upset in the morning and some things i eat upset my stomach too, im also sometimes on edge with my husband. When i sleep im very uncomfortable with blankets because i get too warm. I tested but it came up negative. Could it take longer or am i just not pregnant yet, and yes i am trying. I already have one son(2yrs) it took me 3 months with him to become positive. Would it be the same way?