Reflux or Siezure... or...?

[Pompomdoggles]

Hi, hoping this is nothing to worry about!
Our LG (8 weeks old) gave us a fright during her night feed last night. After feeding her, winding and sitting her up as usual she all of a sudden sounded like she was choking, threw her head back and arched her back and cried, foam/bubbles from her mouth, red faced, tears etc. It seemed like a siezure. She was stiff as a board whilst like this and it lasted about 30 - 40 seconds. We had no idea what was wrong and almost rang for an ambulance.
She seems fine in herself now.
Has anyone experienced this with their LO? Could this be reflux?