I'm glad you wrote. I can suggest a bunch of resources to help you with your anxiety - and I will - but if I only did that, I'd be doing you a disservice. That's because you may be the perfect candidate for good, old-fashioned, insight-oriented, successful psychotherapy.
I realize I don't know you - just what you've written here - but I'd lay odds that it's time for a little reflection on what entering this next phase of your life means to you; on how you perceive 'adulthood' and career; on whose goals you were reaching all this time; and what you want for yourself and your life, unimpeded by the ideas of others. The timing is perfect for chewing all this over with a skilled therapist who has no axe to grind.
Now it’s possible that all you need is a little time off the merry-go-round. Perhaps a few months dawdling on the Amalfi Coast are in order? Or if the price tag for Italy is out of the question, there's always Thailand for a mellow, low cost, change of scenery and perspective. But the degree of anxiety you’re suffering suggests otherwise. If that were it, you'd just feel serious lassitude and lack of energy for moving forward - but it's worth mentioning, because generally speaking, it's pretty weird to reach a desired end-point that you've been striving for all your life.
But as I said, I think your anxiety spiking in such a targeted way suggests otherwise. This is a relatively easy thing to remedy with traditional, insight-oriented, deep dish psychotherapy.
As for the promised resources, one of the best things I've run across is Erin Olivo's Free Yourself from Anxiety – a really impressively put together CD set that addresses all the issues around anxiety and offers good relaxation exercises. David Illig also has a good one, in an Ericksonian, hypnotic style. And of course Mary Sise has an easy to follow meridian tapping program that you can learn simply by watching her video. And my Panic Attack imagery would also fill the bill.
But I'd start with Erin Olivo’s first, and see how that goes - it's the most specific for what you're dealing with.
I hope this helps. Be of stout heart. This is totally fixable.