Hi there, myself and my partner have been trying for a baby using the ovulation tests, we sleep together a few times 2 weeks ago during ovulation. I am 3 days late, for the past 6 months i have my period every 22 to 23 days. It is now day 26 and the past 3 days I have had cramping, lower back pain, fullness in the lower tummy and feel generally off and a bit weird with anxiety. I took a test this morning and it is negative. Could it be wrong?