Building endurance and strength slowly

[caneup]

Hi.  I have SLE, Sjogren's, MCTD, and most recently, I was severely anemic during pregnancy.  I am suffering from deconditioning because I haven't exercised in over a year due to the severe anemia (I don't normally exercise a great deal due to pain and fatigue). My hemoglobin and ferritin levels are back in the low/normal range. I would like to build my endurance and strength back up, but I know I can't do a strenuous exercise program. Does anyone have a good resource for building strength and endurance slowly and gently? 

Thanks in advance!