What's cause my blood pressure to be a little high on the bottom number, could it be a possible sign of preganacy? Never had this problem before.

No. It's not an early sign of pregnancy. Be sure you're measuring it at complete rest for 10 minutes, use a validated, properly sized arm cuff, measure at the level of your heart, take measurements on multiple days and average them. If it averages >90, consider salt intake, weight, and be checked for kidney function with urinalysis and blood sample. Avoid licorice, XS alcohol, recreational drugs.