Spitting up at 14 weeks

Hi ladies. Hope you’re all safe. My 3.5 month old freaked us out he was sound asleep and we heard him kinda like a burp but sounded wet. So I got up to check and realized that he had spit up. It was saliva and formula and had that’s our milk smell. Is this normal? After he was fine but he started gagging and nothing would come up so it freaked me out even more. I grab him and flipped his positive but nothing would come up. I started freaking out cause I thought what If he had something stuck and I checked snd no he didn’t.

Anyone else go through this? If so please send advice.