Welcome to HCM,
As per you, every month your periods started 3-5 days early, which means your menstrual cycle duration is about 25 to 27 days. Ovulation generally occurs 14 days prior to beginning of next menstrual period. Thus your ovulation was expected between 24th-26th march. If you had unprotected sex during or nearby dates, chances of pregnancy
are more. If ovulation has taken place at due time, pregnancy can be detected with test at present. But if ovulation is delayed due to any reason, test result can be false negative. Thus if result is negative, you have to repeat it after 2-3 days to become sure.
Wish you good health.