See how it is tomorrow.
Pressure on a nerve can cause numbness, which will resolve some while after the pressure is released. Do you wear a ring? Have you removed it?
(Is it possible a ring got caught against a knuckle by a carrier bag? Or that a bag was rather tight on your finger?)
If it's still numb tomorrow, check:
Is the numbness on both the little finger and the long finger side of your ring finger?
Can you spread your fingers and bring them together?
Can you squeeze something strongly between your thumb and your index finger?
You should seek medical advice for persistent numbness but my suspicion is that something got squished and the pressure's off now.