Even though sometimes not noticeably, hypomania or highs can follow a positive stressor. I don't know if it is ok to call it a "positive stressor", but good news, little bitty success, acclamation etc could bring down a hypomanic state.

Additional Tips on what could be done:

Be prepared when you are supposed to hear a good news. Observe your feelings when somebody is praising you. Notice if you are trying to say so many things in such a fast manner.

Being aware of the state of the mood is the first step towards overcoming it.

Make sure you are not missing any dose of lithium.( As long as you are on drugs).

Slow down your nerve. Do some breathing exercise. The simplest one is like this: Be in a comfortable position(preferably sit down). Close your eyes. Take a deep breath on a count of 7-9(seconds). Hold onto it for 7 count. Then release it slowly on a count of 14-18. If you are short of breathe, use 5,5,10. Or 4,4,8. The point is doubling the length of exhaling time.

While doing this, feel the chill of the air when it enters your nostril during inhalation, and the warmth of the leaving air during exhalation.

Do this as many times as possible.

Appreciate the good news, thank your lord and set a next plan that will remind you of your burden ahead.