Gas and fatigue and light-headed. Sibo?

Last yr, march I didn't exercise for 15-20 days which caused bloating & it used to cause me anxiety so with consultation i took pan-d and mucain gel for 15 days. But I started controling my diet way too much which caused me to go down to 43kg from 49. It caused weakness. I did endoscopy in sept which showed mind antral gastritis and small hiatus hernia.i was given pantocid-it for 15 days and multivitamin. I felt lot better so didn't go back to doctor & started diet with the help of dietitian in oct and gained 4 kgs in span of 4-5 months. I used to feel weak but much less and was taking zandu pancharisht. Also used to eat every 3 shours. But now again i am passing gas many times , it starts as soon as i eat and i feel weak & light headed sometimes in a day. I now walk for 3 km a day in morning and also following diet for weigh gain.Taking Ayurvedic medicines for this problem and vitamin e capsule and one multivitamin. i want to get rid of this, can gastritis cause this or i can hv SIBO?