Do i have low blood pressure if my diastolic blood pressure is lower than normal range and my systolic blood pressure is normal?

This is not easy to answer without examining someone. Some people have lower blood pressure when compared to the regular population.

It would have helped had you provided the actual numbers, it would be prudent to consult your doctor. For healthy diet: http://www.choosemyplate.gov/., exercise 30 minutes/day, drink enough water daily so your urine is mostly colorless, have safe sex, no tobacco alcohol weed or street drugs. Get HPV and Covid vaccines. Wish you good health!