4 months old baby. Doctors please help.

My son is exactly 17 weeks old. He's full on formula. I tried to breast feed. Tried all methods, medicines, granules, mother Horlicks and all.. but no milk flow at all.. he's on aptamil. Problem is he had diarrhea for 5 days.. we went to ped.. and it's settled now. Doctor gave him econorm. So now problem is he's fussy all the time. Other than playing, and sleeping. Crying all the time.. he had a scratchy throat for day. Other than crying he's all good. Good bowel movement, urine output, achieving milestones.. he's rolled over at the start of 3rd month. I need some reason for his crying. My in laws are constantly asking whether he's crying all the time.  Making me feel depressed. Doctors please help. thank you all.. note: he takes vit d3 drops, his last checked weight last week is 6.25kgs.