Started a New Painting - Yikes!

I have started a new painting and have already put in ten hours - and really you can't tell.  I hope this painting turns out.  I really like the premise.  This time I am painting two full figures in a comical setting; of course, it's of Eddy and me.  I'll have pictures once it looks like something- and again it's all in grays with a touch of color.  It's a big canvas and my arms are exhausted from having to raise them up and paint for so many hours.