Should I be worried if I feel my baby move less than 10 times a day?

No . There is no set of tim's table how often the baby moves , but he is more active at night.
No. Not necessarily. A lot of times, you are so busy throughout the day that you did not recognize all the baby movement. If this is the case, drink a glass of ice cold water (may stimulate baby a bit more), and lie down in a dark, quiet room. You can now focus on baby movements and should count multiple movements in a 30 minute period. Try to replicate this as best as possible throughout the day.