Joedaddy,
In an emergency...it is possible to foliar feed a cutting if it's using up all it's stored nitrogen. In your situation, with a reveg clone taking longer, it may be advisable...but wait a bit longer. I have to say that that cutting demonstrates the resiliancy of ganja plants. That little gal really wants to live!
JD
Edit: That the plant is yellowing is a good sign. It is still acyively metabolizing and using it's stored energy...and hopefully most of that work is going toward growing roots.