I'm so sorry you're having pain, I have been there and completely relate. I'm actually in a situation complete reverse from you I had a lumbar fusion L5/S1 in 2004 and on July 17th I just had a Fusion of my cervical spine - C5-C7.
To be completely honest and I'm not sure this is what you want to hear, but for me the recovery form the Lumbar fusion was MUCH more difficult. In reality ALL surgeries are difficult, but the Lumbar fusion required a lot more special accommodations at my home (elevated toilet/shower seat) and because they cut through so much more (the anterior cervical procedure seems easier healing wise). I think it also makes a difference on if you have a hip bone graft. In both cases I did and it was from the SAME hip (my left hip) and unfortunately that is currently causing me the most pain post anterior cervical
fusion (I actually don't recall that being THIS painful post lumbar fusion).
However, I have to say even though I had post-operative pain from the healing involved, I noticed a difference in my symptoms immediately - it was just a matter of healing.
The difficult thing with lumbar fusion is you can't do a lot of sitting; so that's something to consider.
I can remember I literally having to time the amount of time I sat - it was actually a relief to get up and walk. I did make sure I was up and taking walks by two weeks post surgery. I think that is really important to your healing and I fused really quickly and well. I didn't have a problem until I took a huge fall and as unlikely as it seems it caused a shift which caused the instrumentation to hit a nerve and I began experience a GREAT deal of nerve related pain again and the instrumentation had to be removed. IA .. you may want to check the back board for more answers. I found great support over there as well:
Keep us posted on how you're doing and I will check into the back board also.