I recommend a neurologist if for nothing more than a correct dx. You don't have to get an immediate surgery, just a solid dx so you know where you stand.
I have sacroliliitis and stenosis from bulging discs that also press on the SI-1 nerve. I feel alot of the same thing you describe. I am not a surgical candidate at this time. Not sure I ever want to be one. But in my case only, the PT put me in water. Not swimming, but exercise. It made me much worse! It felt like the leg was popping out of the joint in the groin area. Obviously it wasn't, but it would catch me all of a sudden and my knees would come close to buckling it hurt so badly.
Get a dx before anything.
150mg Azathioprine, Lomotil, Iron, Nexium 2/day, Fentanyl patch, Oxycodone, Baclofin
Crohn's, Fibromyalgia, Several bulging discs, Bone spurs, Osteoarthritis, Osteopenia, Reflux, Stenosis, Strictures, Dengenerating facet joints
When I am weak, then am I strong