Hi I Am Worried Because I Haven't Had A Period

Hi I am worried because I haven't had a period since January and in December me and my fiance tried to have a baby we took a fertility test and ovuLatin test to make sure I was ovulating and the test was positive so we had sex hoping to get pregnant well my period was about a week late in January I went to the ER to get a test taken and my period came on that same day on January 23rd. My period lasted for about 3 or 4 days and I haven't had a period since I haven't had sex again until just recently when my fiance came to visit Feb 20-26th it is now March and my period is still not on so I was wondering what could be the problem because I have been drinking because I was told by the doctor that I was not pregnant