Yes. A lot of times people with severe leg pain don't believe it starts in the back because it seems so odd. In my case, my pain was about 90% in my buttock and outside calf, with very little pain in my back. In a way, this is good news... leg pain is a lot easier to diagnose than back pain. I'm sorry... I'm sure it doesn't feel like good news!
A bulging disc causing mostly leg pain is not uncommon at all. If you haven't already gotten an MRI, try to get one. A fusion may not be necessary if it is only a matter of the disk bulging - that could be taken care of by a microdiscectomy (a relatively minor surgery as back surgeries go), or may even respond to PT. However if you have a scoliosis or a spondylolisthesis or severe DDD you may have to do something more radical - like a laminectomy or even a fusion.
Check out the web and learn all you can about your condition. It makes it a lot easier when you know what's going on. And, of course, ask this board. There's a goldmine of info here and no matter what you're going through there's someone on here who's already been through it.
Good Luck!
David