His and Her Health

i went off birth controll about 4 months ago because my husband and i are trying to get pregnant, now my periods are getting further and further apart and without fail everymonth i am getting all the signs and symptoms of being pregnat im having mood swings and food cravings and last month my breast even got swollen only one problem. im not pregnant after being about 3 weeks late i just got my period again. has anyone experinced something like this , should i be worried? is it all in my head?