PLEASE HELP Mommy is VERY worried & scared!

I woke up about 30 minutes ago feeling her kick my arm. (Yes she sleeps next to us, no judgement please. We're in a r.v with no room for a basinet) I look over at her laying my hand on her chest and I couldn't feel much of a heart beat. So I sat up and saw her what seems like spasming. It looked like she was choking or drowning on something. I quickly got her up and woke up hubby by kicking him. I'm patting her back hoping whatever it was she would maybe up chuck it. It took her a minute to finally breathe correctly and cry out in pain. She hasn't spit up anything. There was a moment I thought she did by the sound of it but there was nothing. Hubby held her patting her back as she cried and well right now he has her in the bathroom (he couldn't wait to go) watching my little pony with her. Lately it seems like she has problems breathing at night and sometimes very seldom during the day. I'm not sure what it could be. I'm not sure if she's choking/drowning on her own saliva or what. I just need answers on what it could be and what I need to do to make sure this doesn't happen again. I'm shaking nearly having a panic attack I'm trying to calm down...I'm glad I woke up otherwise I would have lost her.....some one please ease my mind...I just don't want this happening again...