I have anxiety with exercising, but that's mostly due to the fact that I'm convinced my heart will give out!
If you're suddenly experiencing extra anxiety and can't pinpoint any other cause, you could potentially be over-training. That could create anxiety symptoms. Also, hard exercise does cause the release of adrenaline in your system, which could up your anxiety. I would say either go back down to your previous level or even take a rest week, and then start up again. See if either of those fixes the problem.