Your symptoms could be due to problems in the wrist referred to as
Carpal Tunnel Syndrome. The nerve innervating (supplying) the thumb, the index finger and the middle fingers is the median nerve. This can get compressed in the wrist, leading to numbness of these areas leading to a condition called Carpal Tunnel Syndrome. The nerve can get compressed due to obesity, Diabetes Mellitus, hypothyroidism, arthritis and trauma.