The "normal" resting pulse should be between 60 and 80. If your resting pulse is always below 60, this may explain the dizziness. Dizziness is from the brain not getting enough oxygen. If the blood is not pumped as fast as needed for the brain to get the oxygen it needs, dizziness will occur.
Your systolic (top #)blood pressure is less important than your diastolic (bottom #)blood pressure. And going from 120 to 110 is not bad at all although it may be on the low side depending on your age. If you are an older person, I would guess that you may have low blood pressure. The diastolic blood pressure # is usually very close to the pulse rate. So, assuming that, your blood pressure is probably a bit low. You should go to your doctor. Have him do a physical on you and ask him to check for anemia. Good luck.
"Troubles are often the tools by which God fashions us for better things".
Live, Love, Laugh.