sorry to hear this. you are quite young. ive not heard of Pericarditis, so I do not know how serious it is. though recently I had many similar types of symptoms but not quite the same. it caused a lot of anxiety at first , but many tests and they could not find anything immediately wrong. even now I see a lot of things pertaining to death , maybe I just notice them more, like there is a deep fear or something in my subconscious . these things can cause all sorts of physical and mental issues and thoughts. fear of death started this for me I think.i am on meds for these things and I just keep choosing love now . trying to heal that fear with love when it pops up. I think it was Roger Ebert who said " well I'm not afraid of death , I never had any issues before I was born , so why would I have any after I die". made sense , that is if there is no afterlife. if not you got to figure one would just be gone and not fear or miss anything in any way at all. if there is an afterlife then , well much different story obviously.
I believe one can choose life and love and through their intention and DNA can heal anything and change the future possibilities. good luck with your situation.