Late again

Lauren • 24 years old, mother to a beautiful 7yr old girl. Fiancé and I have been together almost 3yrs & we want a baby!!
For the 2nd month in a row I'm late on my period. Last month was 5 days with a negative pregnancy test, and today is day 4 of late period for this month! Advice? Opinions? I don't want to psych myself out again thinking I'm pregnant because honestly I don't "feel" pregnant, but, 2nd month in a row, late?? HELP!