Just for today don't compare yourself to anyone else. You're ability to train for a half-marathon or successfully get into better shape or switch careers is not defined by what another person does, did or will do.
You define Yourself.
Your steps, your building blocks, your joys and revisions come from You and comparing any part of your day to a big announcement made on social media, company wide email or lunchtime gossip depletes you. You weren't privy to the struggles, the sadness or the failures that went into your friends triumph. So, celebrate the moment for them and for You. Be mindful that you don't compare and lose your focus.