M.J.
Anxiety can make us feel all sorts of symptoms that seem like they are serious, and prompt us to think they must come from a medical condition...but the fact is, anxiety causes real psyiological responses within our systems. These were designed to protect us (either by flight or fight) but now simply leave us with uncomfortable and confusing sensations.
Your docotor's visit further reinforces the fact that you are fine, and simply dealing with anxious effects.
Try repeating this mantra when you are having doubts about your health.
"I am okay, this is just anxiety making me feel this way."
This really helped me through some rough times. It takes some practice, but keep saying it over and over...the words we say to ourselves have power, and can change our anxious thinking over time.;)
You are going to be alright. Keep posting!
S.C.