Hi and welcome to the GERD forum.
I am bumping up your post in hopes someone has some info to share with you.
My daughter (when she was 17) had similar symptoms and after 8 days in the hospital they found out her gallbladder was not working properly, causing similar symptoms to yours, even though all tests were normal. She also had GERD often (which looking back was assoc with the gallbladder issues). In her case she had a Hida Scan in the hospital and turned out it was only functioning 4% so they removed it and she's been fine ever since. They saw her nearly faint in the hospital and did full workup inc. doppler ultrasounds of heart, etc. and all was 100% normal. Just an off the wall thought to share with you in case you aren't able to get any answers.
Several things at same time confusing to your doctors:
GERD doesn't cause dizziness and gaviscon is not how to treat it....
You need an endoscopy to make sure you don't have an ulcer or something else (UNLIKELY!) making you throw up, get dehydrated and then dizzy....
I am forced to mention this even tho the likelihood is super rare-dizziness is a cardiac arrhythmia until ruled out so just have GI doc you need to see run an EKG.....along with labs for dehydration and include magnesium....and if you are NOT repeatedly dehydrated which it sounds as if you are THEN you need a "holter monitor"-don't freak/would be rare-have doctor confirm you have a normal "P-R interval".
Because this is all pretty scary I think you might,on top of whatever MINOR MINOR CAN BE FIXED is wrong,you might also be having panic attacks and that just confuses everyone.
So here's what you do:
1. Get pharma grade digestive enzymes +betaine like what I give and take that for your GERD
2. SEE GI M.D.
3. Breathe deeply and relax
4. If nothing turns up with GI doc then get a Holter monitor with a cardiologist,again think this is highly unlikely and do NOT get nervous!
For over 3 1/2 years (since I had my daughter) I have dealt with a range of symptoms : brain fog, feeling "off", feeling dizzy, feeling like im gonna pass out (eyes are dilated when this happens), heart palpitations, tingling, numbness, shaking, cold, night sweats, leg cramps, belching. I was scared to be alone with my infant daughter, thought I would pass out! I noticed my symptoms would ease after a bowel movement (in which my head would tingle every time). Been to ER numerous times...told every doctor same symptoms. ....had CT, MRI, bloodwork, heart monitor, endoscopy, Hpylori test, SIBO test, celiac test, tried Nexium, tried gluten free diet...all negative and still sick. I swore my doc thought i was crazy so i researched myself. ..and thank God I found a forum where this guy thought he was allergic to corn from the time it entered his body til the time it left his body he was sick. I called my doc asked for a food allergy test and thank the good Lord I have my answer! I am allergic to SOY!! Pregnancy changed my food allergies because I was not allergic before. It is very hard to avoid because soy is in everything but I have not had symptoms since I have been avoiding soy!! I definitely know if I slip up and eat something with soy!! I hope my post helps at least one person because those symptoms are truly debilitating! It was the post of another that gave me my life back! God Bless!!