I go on my periods every 2 months/ever 55 days for the past year. this time around i'm on day 66 but still no period. i took a pregnancy test and it came out negative. when should i consult the gynae?

Irregular menses : An early look at your menstrual history over the past year by your gynecologist would be helpful at this point. If this pattern of not having periods repeats itself, it may be necessary to treat you with hormonal treatment to regulate your cycle which is more healthy for the lining of your uterus.

"Periods delayed" ?: Having "periods" once every two months may be caused by polycystic ovarian syndrome (PCOS). The "periods" are usually just bleeding episodes, without ovulation, caused by sustained estrogen thickening the lining of the uterus. See your gyn physician, who may order pelvic ultrasound and recommend low dose BCP's, the treatment of choice for this condition, to preserve fertility.