93 days no period negative pregnancy tests

Kaili • 25 years young ttc my number one have 2 wonderful sons that are from my husbands past relationship. EMS
My fiancé and I have been trying to have a child for the past 6 months and have failed. I've always been regular until a few months ago it came to a complete stop. No signs of one or anything. No clue what's going on. Anyone experienced this for this long