We have to live each day with purpose and strength. If you don't matter in someone's life every single day, then honey, you're not living at all!
Sometimes, it is difficult to have a mission every day if there's no 'boss' to direct us, so you have to keep in mind that now you're your own boss. Make a list of 'things' to do each day that will still keep your spot marked. Open a door. Give to the food bank. Call someone just to say hi. Hug someone.
Keep living. That's all. Just because you don't get up and go to work every morning doesn't mean you don't need purpose. Keep creating a purpose and you'll stay in stock and on the shelf and your life will remain full.