Misery doesn't like a company. Much of your problem alleviate from lack of a good company. Allow me to suggest few things.

First and foremost, nobody will knock your door and ask you if you can be their friend. If somebody did, then run!! Jokes aside, you have to take the initiative to goto places where you will meet people. Talk to your friends, whoever is left now, and see if you can tag along to goto gatherings with them. You will meet new people this way. Be open to friendship from people of every demographic.

Join meetup groups. There are plenty of websites (meetup.com). You must have a hobby or sports that you like. Just going there to play and enjoy will help you earn friends; trust me there are sports of every level out there.

In all of this, be yourself. Don't get into bad crowds and horrible habits.

Let's start with a plan. Tomorrow, I want you to wake up an hour earlier than you normally do. Waking up early in the morning makes your day so much brighter. Do some simple yogas or cardio. This will give you a good start. Now smile and keep a positive outlook. Talk to people, bring that smile in your face and you will feel better (this is a proven method).

Once you have more friends and better company, your perspective will change itself. Having a short-term and 5-10 years plan will also help.

Good luck. Let us know if you need more help.