It can feel like a piece of you is being left behind - even when the obvious choice is to move on. It might feel like a relief as the burden and risk is removed.The feeling is not very relevant to what needs to happen next - which is move forward.
Do it. Hold your head high.It is a choice.
The future has new discoveries. The people you meet in the future will be important to the next success. (Make introductions)
Write the story down. The mission. What happened. What was the critical point? What will happen next?
Serve others. Volunteer to help another get something done. You will inspire and as a result, be inspired.
Listen to "The Dip" audiobook by Seth Godin on Audible. It will have the answers you hope for.