Two months seems about right for your muscles to be in that awkward state - Not sure of the right terms for it but basically the idea is that your old existing muscle mass from when you started is trashed and the new muscle mass you've been building is not fully developed. You are probably weaker now than when started commuting. A little rest for your muscles may be the best thing you can do.

I'll be in a minority here or perhaps even an island - but I say drive the hill for the next couple of weeks then hop back on. You still want to do some excercise but you need to lighten up for a bit for muscle recovery.
If you continue to do the hill, spin in your lowest gear.

FWIW