How do I achieve inner peace when my mind is full of ideas?

Why dont I feel contented all the time?  I do sometimes have moments of feeling complete calm.  Feeling really centred.  Feeling at peace in myself.  And my meditation practice is then a pleasure.
Then other times, I feel so driven, so invigorated and motivated.  Restless, buzzing with ideas and thoughts.  Feeling like I want to be doing more with my life.  Being of more value and service to the planet.  Making a name for myself.
Is this all ego?  Or is my souls higher purpose calling me to claim my place on this earth?  Possibly a bit of both?
I do know that spending time in nature (especially woodland) frequently and regularly has an amazingly calming effect on me.