Thank you for your question on ehealthforum.com
A delayed positive pregnancy test can happen occasionally and it may take a few weeks before it gets positive. If your pregnancy tests were performed in the very early stages immediately after you missed period, then it is a good idea to have another test in the laboratory.
If the test is still negative, then other causes of amenorrhea (lack of periods) need to be ruled out as this may require hormonal assay, ultrasound scan apart from physical examination by gynecologist. So, please make an appointment to see a gynecologist for the test and examination. Thank you