Stop cutting yourself off from your friends and family. The fact that they call you and celebrate your birthday shows that they care. Dont be afraid to speak to them about your problems. All of those other things, being productive, proper sleep schedule, will be much easier with social support network.
Also having some pleasurable experience during the day and expecting it to happen also the next one gives you motivation to get through the day. Set up some time for something fun every evening, be it conversation with a friend, a video game or jerking off. But try to follow a strict schedule with it.