I'm so sorry to hear things are so stressful for you right now. You'll definately be getting prayers sent your way from your friends here.
Since you're doing the cooking and cleaning for the elderly,could you get some help from a church or civic group? You could also contact the Girls Scouts or the Boy Scouts and ask for some volunteers(It could be a good "service" project for them)
Heres my prescription for "Stress Relief"
Close bathroom door,run a hot bubblebath,pour a glass of wine(just 1,cause your destressing not escaping),light some lavender scented candles,turn on some nice music and set the timer for 1 hour,refill hot water as needed
May be taken as needed