Im on period time but didnt got normal bleeding it was very light.it was my second day is it the sign of pregnancy?

Probably nothing: The menstrual cycle is sensitive to many things (weight changes, stress, medications, etc...). Depending on age, menopausal status and other factors, this may need to be evaluated asap. Keep a strict menstrual diary and follow up with ob/gyn if pattern continues more than 3 cycles. Finally, when in doubt, ALWAYS do a pregnancy test.