I feel numb on my hand and fingers?

Many things: This could be from many things: nerve inpingement, nerve damage, sodium or electolyte issues, glucose issues, repetitive injury, carpal tunnel issues, other neuromuscular disorders or even a sign of a heart attack. If this persists/worsens seek attention from a physician for further eval and management.

See a doctor: Numbness in the hand an fingers could be the sign of nerve compression anywhere along its course- from the neck to the hand. Symptoms can resolve spontaneously after changing position or with time. If they do not, you should see your doctor.