Baby choking and can’t breathe

Ga

I need some help. This has happened 2 times in the past 3 days already. My baby is 2 months old. The first time this happened I set him down to change his diaper then he started making a gulping noise and turned red and threw his head back and started flailing his body but was stiff and sounding like he was choking and couldn’t breathe. We picked him up and started patting his back but it scared the crap out of us. He did this again this morning while sleeping, luckily I was barely falling asleep so i was able to hear him and I reached over and removed his swaddle while calling for my husband when he then jumped up and picked him up and began patting his back. Its scary because he can’t breathe and I’m scared he’ll stop breathing all together. I think it has to do with his saliva? He’s been drooling ALOT and I don’t know why. He has excessive saliva or mucus in his mouth that I have to suction it out with a bulb syringe very often. He constantly has drool coming out. His doctor says he teething but I do NOT think he’s teething.

Does anyone know what’s happening?

Why is he randomly choking??

Why does he have a lot of saliva and drooling a lot??

I’m a first time mom and I’m now scared to sleep cause I’m afraid I won’t hear him next time

Edit: obviously I asked his doctor When it happened the first time, She told me he was teething. I’m asking on here to see if anyone else had experienced this to see what they were told. Also,it’s Sunday, his doctors office is closed and they don’t have a hotline.