Sorry to hear you're freaking out again, but SURELY you know in your rational mind that this is all a product of your anxiety.
If the zoloft is causing bad side effects, either try to ride it out - they usually go away - or try another medication; there are plenty. There are also anti-anxiety drugs that might help you if an antidepressant isn't enough on its own (I would suggest from personal experience to get some that you use as-needed rather than regularly as a preventive; but that's just what worked better for me.)
There are therapists and doctors who can help you. You have PROOF that you're healthy. You have heartburn, one of the most common nuisances in the world, and your brain is telling you this is a catastrophe. You need to find someone who can help you take control back, and take it back, because you can't live like this. Your family needs you functional.