Hi dizzy128 and welcome!
I am sorry that you are currently dealing with this issue.:( I know that it is scary and confusing to go through.
What you are likely experiencing is the sensation of a near faint or seizure type episode. This is a pretty common concern with those suffering anxiety.
It is rarely actually occurs...but the feelings/fears of it happening can be very convincing!
The good news is that you have checked out well from a physical standpoint, so you can now focus on reducing the anxiety and symptoms.;)
Here are some exercises that should help. Practicing these relaxation skills and breathing techniques will go a long way in reducing your symptoms.
Self Help sites with breathing/relaxation exercises instructions
Panic attack relief exercises:
Commit to trying these 3xs a day for at least 10 min a session for a week and see how you feel.
Keep posting with us as well. Support and understanding is key. We are here to listen anytime.
"Courage is not the abscence of fear, it is feeling afraid and doing it anyway!"
"Worrying does not empty tomorrow of its troubles...it empties today of its strength."
Corrie Ten Boom
Panic Syndrome recovery due to CBT