Stinky farts

I'm a FTM My baby is almost 7 weeks. Breastfed, occasionally say 3-5 a week I give him formula. He hasn't pooped for 3 days, his farts are super stinky and he is very agitated. Cries, farts, doesn't sleep and is spitting out milk. I can hear the milk gargling in his throat sometimes. Don't know what to do. 😔

Have mentioned it to the dr multiple times.. they say he'll grow out of it, its colic and reflux gets better as they grow. I have tried gripe water and Infacol. They help sometimes. But since last two days he has been super agitated. What do I do?