There are no answers, only ways of coping with this strange life we have been given. This life is an opportunity - our challenge is to make the most of it. That doesn't have to be taken in a cheesy motivational-seminar kind of way, but there is truth in it. Doesn't mean that you should feel an obligation to 'pick up your socks' and become a power-achiever, indeed it is isn't necessarily about achievement at all, but rather about finding the peace that resides in your heart - and all around you, and embracing it. It is about realising that you will never know any 'answers' only questions, and deciding what that means to you. For me, learning to go with the flow on a daily basis, to try be as non-judgmental as possible, exercising and meditating regularly, and generally trying to stay with the centre by avoiding those things which knock me around is the best way to keep the black dogs away. And then, when you are feeling good, it is time to help others, even if it is only in simple ways - for example, educating yourself is a way of helping others, for by becoming more knowledgeable, you will have more to offer others as you make your way through life.
Most importantly, give yourself the right to despair - this may seem strange - but it is alright to feel bad, and when you do, not to beat yourself up over it. Darkness always turns to light again.
*Thanks to Kayla for the inspiration.