Well, the chances of getting a job in high energy theory ARE nonexistent, except for two groups of people:
If you aren't in one of these groups, then forget it.
It's easy to tell whether or not you're in group 2, but somewhat harder to tell whether you're in group 1, as you point out in your post.
I think the best way to compare yourself is to crawl around on the web to find the websites of current youngish theoretical physics professors, and then look up their bachelor projects, master/PhD theses, and early papers. Are you at the same level as they were? If so, maybe you have what's needed.
Oh, and it goes without saying that you should be doing physics 50-60+ hours a week, at least. Otherwise you have no hope of ever catching up with the field. HET is a tall, narrow mountain to climb.
But ask yourself, why do you want to do high energy theory so much? Have you looked at any recent string theory papers lately? Pretty boring IMO. The field has kind of dried up these days. Sure, it's fun to learn about all the cool theories that came out in the 80s and 90s, but since then things have slowed down. I think it would become pretty tedious if you were stuck in those horrible computations as your research job.
Personally I see much more interesting stuff going on in quantum info/computing, astrophysics, materials, and nuclear/atomic physics. And these are all fields that also require theorists, if that's the type of research you're most interested in.