I don't know how typical this is but perhaps you will find it encouraging. I had a PLIF at L4-5 with a cage, roRAB and screws in Jan of 08. As I mentioned earlier, the first eight weeks were very difficult. However, between about ten and twelve weeks there was a great deal of progress, and I started to feel a bit normal again. At 12 weeks I was able to fly half way across the country and spent five days looking at real estate with my son -- I would stretch out on the floor at night to rest my back and I remeraber icing every night, but I felt OK.
By four months, I was getting my strength back and feeling more energetic and by six months I felt more or less back to normal.
Don't worry about not having started PT already. This is an individual decision depending on your surgeon's training and experience. Some believe in starting early and some don't like to start until there are signs of bone growth, etc. The surgeon my MIL had for the same surgery did not believe in PT as a general rule, because he had seen too many cases where it caused more problems than it helped. So you can see, opinions range all over the place. Again, I reiterate: walking remains your best activity. It is best to walk a shorter distance several times each day than to take one long walk. It helps to keep those spinal nerves stretched out unlike any other activity you could be doing. And early in recovery that is one of the main things you want to accomplish -- stretching out those nerves to keep scar tissue from forming attachments.