15,000 in 24 hours is a lot. I had 12,000 over 72 hours which = 4,000 pvcs a day. My dr. wanted to ablate, but I want to wait, as I read a lot of drs. wont ablate unless you are having 8-10,000 a day. If you are having 15,000 I am curious if your dr. wanted to ablate? Momto3 on here was having 20,000 I believe and she ended up with cardiomyapapthy I believe, which my dr. did mention to me---which is not common, but yet an issue with many pvcs. If you can, you should talk to her. She had the ablation and I believe is doing well. I am not sure if other people just live with them in that high number or not.
Sorry I can't be of much help, the technical details are "over my head" and I don't know what Metoral is. If it is or contains a beta blocker that could cause some of the symptoms you list and they may pass as your body adjusts to the medication. Again, I don't know the medication as it is not sold in the USA (my reference).
The 15,000 PVC looks "bad", but I guess that depends a great deal on how much they bother you. For example, I suffer constantly (permanently) from atrial fibrillation and that cuts back on my physical endurance, but otherwise it doesn't bother me... so my doctors are not very interested in trying to stop it. I think a similar strategy applies to benign PVC cases, with I believe are most of the cases. The Metoral may help reduce the number of PVC, I assume that is the reason it was administered.
Good luck, hope you get better soon and you find the information that will help you deal with the real-time issues.