I do something rather mindless. I make a simple no patchwork crib quilt. So I get a few ready to sew binding on while watching tv. Gives me some quilting to do and I don't feel lazy and accomplish a bit.
Sometime a messy sewing space can cause problems. Am sure you don't have that problem lol but I do
Look around and try to discover why you feel the way you do and then go about changing the cirumstances. If the projects just don't interest you now. Do something else - perhaps a simpler one that can be finished quickly.