I was in a restroom in the airport, and i believe someone came in and started throwing up. i was wearing a kn95 mask and left within a few seconds. i dont think she was next to me, but was in a stall around 10 ft from me. did i catch something?

Very unlikely. However, if that person was vomiting due to norovirus -- the most common cause of viral gastroenteritis -- it is conceivable you were exposed and could be infected. However, your mask would have provided very good if not total protection. I wouldn't worry about it.

Not likely, hand hygiene remains best after using public restrooms in preventing possible gi infections. Nausea and vomiting, commonly seen in infections may be due to a variety of non infectious medical conditions.