I want to be comfortable in a resturant

I had gone out to a restaurant for a small family thing. It wasn't packed but it was mildly busy. My social anxiety ended up kicking in and i couldn't even eat two quesadillas i ordered (we went to a Mexican restaurant) because the nausea was so bad ;-; 

I wish I could be comfy enough to go to places like this. I can handle stores, I can handle going to other peoples houses somewhat. It feels almost embarrassing i can't handle being in a restaurant of all places. i'm hoping i can get comfy enough to be in one at least for an hour, possibly even longer someday.