Advice please

My last period was December 20th. Was supposed to start on January 21st but it still hasn't came. I tested and got a negative. I've been taking ovulation tests since I never got my period they have all been negative except yesterday and the day before that they were very positive. I'm so confused about my body and I called the Dr they didnt seem to concerned :/ I've been ttc for about 4 months now.