Stress induces anxiety.

I don't think its a new manifestation of your BP. I think it's in relation to the current stress you're experiencing. If you didn't open with "Been going through some extraordinary stresses at work lately", I would have agreed that it could be a new manifestation of BP. People who are BP tend to be sensitive to stress and stress is known to trigger episodes.

Breathing: Three Exercises - Dr. Weil

Here are some breathing techniques you can practice that also help reduce anxiety/stress.