Talk to Pediatrician on No Weight Gain For Months

My 18 months old son is on mother feed and takes 4-6 ounces of nido 1+ twice a day. He is very active alhumdulillah..he takes solid food almost every thing (becoming a bit fussy nowadays). 2-3 months back he got diarrhea with fever. Then his weight was. 10 kg.. A week ago. We checked at home and his weight is still 10kg.. He eats rice., eoti, bread, fruits, yogurt, chicken and selected vegetables..

What should I do? Should i see a doctor for him?