Here is how I got rid of panic attacks and severe depression without pills:
Meditation. One hour a day at least, done in the most disciplined way possible. I used as a manual Mastering the Core Teachings of the Buddha by Daniel M. Ingram. The guy also has a forum.
New goals to fight and work for. Break your routine by all means. Set fantastic goals and follow them no matter how distant may they seem. Change your personal agenda, filling in projects that you think will be good for you.
Workout. Go to the gym regularly. No matter how trivial it seems to be, physical exercises are an organic part of your well-being. More obviously than anything you are a body.
Something I shouldn't recommend publicly, so I will just refrain to report as a personal experience: psychedelics. They have shown me that 1. there is no end of the road and 2. it widens as far as you walk on it. But that's me and as it goes into the debated field of spirituality, I prefer to forfeit it as an advice.
Go out and meet people. Don't let them come to you. Go up to them and make friends. Having people around from time to time is a magic situation to be in.
Don't forget that great depressions and huge internal breakdowns have tiny little causes. You don't need to lose the world to fall into despair. it's enough that someone you love didn't say hi.
Suicide thoughts are thoughts and so they come into our minds willy-nilly. We cannot stop them but they are as immaterial as any other absurd scenario the brains may plot or contemplate. They even don't exist. Meditation will lead you to this attitude.
Know that life is meant to be very tough. The opposite examples are misleading and spring from pure luck. Live is a training, it's hard and tiresome and you have to believe that all this suffering will lead to fantastic results if you do it right, tirelessly and with a positive attitude. You are just scared of the uphill you (and all of us) are facing.
I don't know if I managed to correctly encompass the kind of attitude leading to a happy living... I just hope so. Take care.