I have had weird palps for years, often hundreds per day, so I have some idea what you are experiencing. LIke me, you have had a lot of tests and for the most part come up healthy, which is really frustrating and frightening. You say, "I am so upset by these palpitations all day and I am going crazy... I am beyond overwhelmed and desperate for relief..."
Your emotions are easy to understand. If you are not feeling faint or physically sick when you have palpitations, and are not ready to consider ablation, I will make a suggestion to you: Although everyone has occasional palpitations, not everyone is aware of them. Those who do feel them, I think, are more sensitive to their body's signals, and sometimes that is a hurtful thing, especially if the signals don't have a heck of a lot of medical significance.
I have found it very useful to take one of the SSRI antidepressants for a couple of months when my palpitations drive me nuts, as happens every few years. These medications give the body's alarm system a chance to cool off and re-set itself, in my shrink's terminology. If you have a doc you trust, you might ask him about a trial of, say, Zoloft, which is one of these SSRIs. It can be much more effective than Xanax, for example, in calming the kind of anxiety these palps can cause. Furthermore, I find that when I take Zoloft, after a very short period I am not only much less aware of these funny beats--but they actually become less frequent.
The treatment you need id the EP study and ablation. No medications (apart from arrhythmics which can have serious arrhythmic consequences) are likely to stop the palpitations, and you need to have the EP study and the ablation. Depending on what they find, the procedure is likely to be 90-100% successful for life. Not many other procedures have this kind of life long success. And I do not suggest taking high dose of benzodiazepines, especially in such high doses, as these can have serious health consequences, including respiratory depression and even death.
I also wanted to add that I avoid all triggers, I do not use caffeine, smoke or use alchol.