I've read a lot of people having very low libido when using Nolva. I know people around here say it is better than Clomid, but from user reports I see much more libido issues reported with Nolva.
I would just give it some time, and get blood levels checked in 3 weeks to see where your levels are at.
In the meantime you could add:ZMA,Maca,Avena Sativa,and L-Citrulline and maybe even Muira Puima to boost the libido. Or just get some Viagra or Levitra.