My son is 2.5 years old. He has been suffering from constipation for a long time. He has been on duphalac for 5 months, than he had gastroenteritis and I stopped administering duphalac. However, his constipation is worse i started duphalac again for 2 weeks now, 20ml in the morning and 20 ml in the evening but with No relief.He is also constantly with gas, bloating and very irritable, what can i do to relieve his constipation