This is a hard lesson to learn. If you can learn it then your ahead of the game. I actually think that people who are more sensitive and caring feel more quilt and anxiety than others. People that wear their heart on their sleeve.
Sometimes the best thing you can do is not think, not wonder, not imagine, not obsess. Just breathe, and have faith that everything will work out for the best. For more quotes and inspirations: http://www.lifehack.org/289857/sometimes-the-best-thing-you-can-not-think?ref=ppt10