I'm 34. The childlessness thing is not something to worry about yet. Really.

It sounds as though one thing NOT in your life right now is a set routine of stress relief- you have a stressful job, a lot of anxiety thought habits, and you don't mention any place where you're regularly working to downregulate your physical state, long enough to relax. Do you get exercise? That's part of the process. The other is having a regular place where you try to relax your muscles and calm down, for practice, whether it's through tai chi, yoga, meditation, or just a relaxation tape done at home. Having these things, even for five minutes a day, gives you a regular habit of calming down, so that you don't have stress building on stress. Later, you can take those techniques into the field and into regular life, letting you calm down whenever you notice stress.

my therapist asks me regularly, where do you feel the tension? And when i say, my shoulders, or my arms, or my legs... "What happens if you just give the muscles in your shoulders permission to be tense? Tell them they can be tense." That's usually enough to make me stop fighting to relax them, and they relax. This might be something to practice whenever you notice the physical symptoms getting bad, just as a place to start. But having the set aside time for exercise and relaxation might help you feel as though your life is regulated and not out of control.