I want to add that if you are always under stress and anxiety this can cause some bad stomach issues like your throwing up, but also diarrhea. You didn't mention it, but if you're constantly throwing up and having D it can lead to loss of electrolytes which can increase the frequency of your palpitations. Since you've been to the hospital I'll assume you've had your electrolytes checked, but you never know. I only mention this because the last 5 months I've been having some stomach issues and my electrolytes are always low unless I make a point of consuming more (than I usually would), which has caused an increase of palpitations from time to time. So now I make a point of drinking a couple glasses of V8 per day (high in potassium).
I would say since you have been tested to have a healthy heart despite the pvcs and pacs you may want to go and get your stomach checked out with a gastroenterologist. Acid reflux and stomach ulcers can be made worse by stress and anxiety not to mention the meds you are on could be irritating your stomach and when your stomach gets irritated the vagus nerve gets stimulated thus sending signals to the heart causing it to act up. correct the stomach ailment and you may at least lessen the amount of ectopics you are getting due to stomach issues. I do hope beyond meds you are taking steps to also learn how to manage your stress and anxiety when it occurs. As well as learning breathing techniques like slowing your breathing down to try and make it steady and calm when you stress? Well I do hope you are able to get to the bottom of this. I would highly suggest seeing a doctor to get your stomach looked at. Take care and keep us posted how you are doing.