therapy

Been writing letters to myself every day all month and re-reading them at night. One of the best parts has been re-reading them and seeing myself say nice things to myself. Then was thinking, I've done a good amount of gratitude journaling/affirmations, but then forget them after I'm finished for the time. Anyone know of an app or service that sends you notifications or texts throughout the day as reminders of the nice things you are able to think about yourself? 

If not, I might have to make a super simple one because I think I'd like to get a buzz once or twice a day reminding me of things I like. It's put a smile on my face re-reading my letters at night and I imagine this would too.