Hi I am sorry to hear that you are suffering with pericarditis. I suffer with it chronically. As to getting rest, I sleep propped upon three pillows at bed time. I also have issues with my breathing and complex sleep apena issues, so I'm on oxygen 24/7 and use a VPAP machine when sleeping.
The only thing I find that truly relieves my pericarditis is high dose steroids and a drug called colchicine. It's a drug used to treat gout, but they have found it helps pericarditis. It does cause issues with diaherra. I am currently taking this medication for my recent bout with pericarditis. My cardiologist said I will need to be on it at least 3 months. I have had lupus a long time, and have some other serious health issues. I can feel for you, I would try to get some help with the children so that you can rest. Stress makes lupus so much worse.
If I can help with anything please ask away.