I do have that "loss of vision" but my legs still stand firmly on the ground. Because I think I can stand firmly so everytime "loss of vision" I'll stand still and wait for the vision come back. Sometime just a little bad luck then would hit on the floor. Anyway, I woke up each time...........
I saw many bright stars, slowly the stars fill up all my vision.... I was catching of breath too at that time. I was anemia and also have palpitations-svt. My cardio can make that happen to me while was having my pacemaker check up!
You really need to have a full workup. I have never heard of anxiety/stress causing someone to collapse although I suppose it is possible. I suffer from panic attacks and have felt close to fainting before but never have. It could be any number of things causing your symptoms.
I would ask for a full cardiac work-up, MRI of the brain and full bloodwork just to be on the safe side. There are a few heart arrythmias that young people have that can cause symptoms like this so it is best to rule everything out.
Good luck
It could be a seizure. The time you didn't pass out you may have experienced an aura that did not progress to a full siezure.
One more thing. When I fainted, my boyfriend said that my arms were thrembling.