Hi DAJ819, and welcome to the board!
Did you have any problems with the right leg before surgery? It sounds like nerve irritation. Nerves do take a long time to calm down, but they probably will in time. Like your doctor said, try to be patient. I had some numbness, not as much as you're describing, but it has completely gone away. I had my last fusion in Sept 2006 and a hardware removal in Sept 2007. The hardware removal actually caused more numbness than the fusion. Go figure.
Is your doctor giving you enough pain meds? Are you taking the max you're allowed? If what you have isn't covering your pain, you do need to talk to him about it. Once the pain gets ahead of the meds, it takes much longer to get it back under control. Are you using pillows at night to prop your knees or to prop your whole body when you're on your side? That might help. Are you in a lot of pain at night or just can't get comfortable? I find that I have to regularly turn from side to back, then to the other side for a while, all night long. Otherwise I'm really sore.
You've made it through your first three weeks! Go you!!! That's great! Keep listening to your doctor, no BLT's unless it's a sandwich (no bending, lifting, or twisting

), and walk as much as you can tolerate. Walking increases blood flow around your spine, which is essential for bone growth. But don't overdo it. You don't want to increase your pain, but walk as much as you're able. Most of us don't start PT until 3-4 months post op. Then you'll start working on your core muscles and just getting general strength back.
Even though you've made it through the first three weeks, you might still benefit from some of the suggestions in the thread at the top called, "Post Surgery Tips." There are tons of great tips there.
If you have other questions, please ask. We'll do our best to help you from our own experiences. We're not doctors; we're just ordinary people like you who have a variety of back issues, and a lot of us have had fusions.
Hang in there. It gets easier, but don't rush it. Your job right now is to LAY AROUND BEING LAZY!

Watch a movie, walk around for a bit, read a book, walk around for a bit, watch another movie, walk around for a bit, etc.
I wish you the best as you continue to recover,
Emily