Could i have a negative pregnancy test if my period was months late?

If not pregnant: There are other causes of delayed periods, e.g., ovarian failure. Pregnancy tests, like any other lab test, are not infallible. You may wish to consult your doctor.

Amenorrhea: Yes, it is possible. Some teenagers can miss their menses within the first year of having their first menstrual periods and this is normal. Some conditions like pcos can interfere with the frequency of one's menstrual cycle. As well, female athletes can experience the same situation.