13 DAYS LATE

This is our first month TTC so I didn’t expect anything in the first month but I’m currently on CD 49 and 13 dates late from expected period, I’ve been tracking my periods and have yet to miss a month in almost 2 years, tested this morning using first response early detection and still getting negative. Is it possible I could still be pregnant and it’s just taking longer to get a positive result? Has this ever happened to you and if so what was the end result for you?