Well you can engage in Opposite Action:

For example, if we are feeling very depressed and low and like no one wants us around and we might as well just stay in bed, a way to act opposite to the emotions is to get ourselves up and do something (go for a walk, go to the grocery store, visit a friend, go to therapy, etc.). We are not denying our emotion, but we are challenging it by acting opposite to it. Instead of staying at home in bed, we are getting up and going out. We may not see big changes, but little by little we will notice changes in the way we feel.

Challenge your negative thoughts. Instead of calling yourself "worthless," or "undeserving," tell yourself that you are just going through a rough time.