Well, what CAN you be sure of? Death, I know someone is thinking death. Well, I am already dead, so... I repeat: What can you be sure of?
How can you be sure of life, I should say?
How can you be sure that everything will not just slip through your fingers at any given moment?
How can you be sure that everything you know will not just fall apart?
How can you be sure that everyone you know, every friend you have, is really a friend?
...and how can you be sure there is really something to live for?
Why do people take on others' problems when they are clearly under enough stress? To help others, you have to help yourself first. How do you expect to cope with ANYTHING unless you are sure of yourself first?
Why do people put themselves under so much stress that they spend two days or more sulking and depressed about things that they cannot control?
If you cannot control it, then why bother trying to? I am not saying abandon everything, but just step back and ask yourself, is this really necessary? Is this the logical thing to do, or am I doing this because... I feel like I have to?