your last sentence really is right. whether you ate something that turned out to be bad or you're dehydrated or if it was blood sugar or whatever else, you'll pass it and things will be fine. happens to everyone. i doubt anything will stick around, just happens and sucks. i hope you're feeling better now physically and after a while you feel better with your anxiety as a result.
try to not beat yourself up about your anxiety. everyone is anxious about something.