One of the things I've discovered is staying inspired is work.
Motivation can come from the inside, but I believe to keep moving forward, it's a good idea to constantly see new forms of it.
Do you get the Darren Daily podcasts? Read inspiring, motivational/life coaching books by people like Ken Blanchard, Jim Rohn or Napolian Hill. Not running a business? Don't think you can't learn something from a book about business and how it applies to life. Successful people who share what keeps them motivated can still inspire you in your daily life. I love Stephen King's book; On Writing. Yes, its about writing but in this book he tells the story of how he got to where he is today. His story about never giving up and doing what he loves is inspiring and can be applied to any walk of life.
Look up quotes of inspiration and hang them where you can read them everyday. A daily reminder to keep positive can go a long way in setting up your day.
Check out You Tube for inspiration. Type in the word; Motivation and see what pops up. Check out a few and if you find a speaker you like click that subscribe button so you get their latest updates. You don't have to commit to watching/listening to them all or even listening to the whole thing, but one might pick you up when you're loosing the will to push yourself.
Some kinds of motivation will click, some won't. Try them all and keep the best. Here's a few of my favorite quotes! What are yours?