My Periods Came After 51 Days When I Did Urine

My periods came after 51 days when i did urine test at home there was light pink line on 7th jan and my periods came on 15th jan....my doc is saying there was no pregnancy but asked for follicular study test. Is it ok to go for this test n ofcourse we want a baby now. We were neither using any contraceptive nor my husband leaving the semen inside.