Accept the love and affirmation offered by your family and friends. This will eventually help you to feel more positive about yourself. Make yourself go out with friends even if it is the last thing you feel like doing. Take care in your choices, though. It may be better to go and see a movie or have dinner with a one or a small group of friends than to go to a party where you might feel pressured to have a good time.
Treat yourself in a small way each day; this may be just buying yourself a cup of a coffee, or going to a bookstore or gallery.
Allow yourself time to recover, and to look both outside of yourself and inward for ways of expressing how you feel. Journaling can help you get your feelings down on paper, so you can acknowledge your emotions and figure out how to make changes. A kickboxing class can let you get out your aggression and feel stronger.
Avoid doing things that ultimately make you feel bad. Don't hang around your ex's old haunts, or impulsively text or call him. Feel proud of yourself each time you resist an urge like this. Allow yourself to look at photographs or listen to "your" song, but then stop and move onto something else. Aim to fill your time with interesting places, people and activities.
Focus on some of the things that the relationship stopped you from doing. Most relationships involve sacrifice, and if you were the one trying to make the relationship work, you were probably the one making the sacrifices. Seize this opportunity to travel or to do some of the things you have always wished to do. A failed relationship depletes a lot of emotional energy. See this as your chance to channel that energy into something positive for you.