I'm certainly not an expert, but it sounds like it could be either. I think it depends on what you're thinking when you're wanting to jump and run. If you're thinking about a specific tramatic incident that happened to you before, then it's probably PTSD. If you don't have a specific tramatic incident, then it's probably anxiety.

Either way, it's probably a good idea to ask a t or pdoc about it. Good Luck.