Is it normal to feel sad for no reason at all?

It's just something that happens out of nowhere...it's very rare but it does happen...ever since I was 4 or 5...I just feel sad, like I don't want to do anything anymore or talk to anyone, like I feel alone even when I'm not...a person could go to the end of the world just to help me and be there for me and I would still feel alone in this state of sadness...it usually lasts a couple of hours and then I'm back to myself again...I was just wondering if this is normal and if not what should I do about it?

Howard - he's an engineer and can help with actually building useful things. Allergies might be a problem, though
Bernadette - Smart, tough, and has a doctorate microbiology, which is useful when dealing with the zombie plague. And Howard wouldn't go if Bernadette didn't.
Sheldon - Eidetic memory means he'll probably be able to remember random crap like folk remedies, tying knots, and other obscure but potentially useful stuff. He'd be a pain in the *** but useful nonetheless.

Doing a project. If you could answer the questionnaire it would be a lot of help.

Nature vs Nurture Questionnaire

1. Do you believe your life has turned out the way it is due to your genetic makeup?
a Yes
b No

2. Do you believe that the traits you possess are attributes from your parents?
a Yes
b No

3. Do you believe that people, such as criminals, are born bad or are corrupted along the way?
a Born that way
b Corrupted along the way

4. Which do you believe has more influence on one's personality?
a The environment around it
b The genetic makeup

5. The hobbies you possess are similar to your:
a Parents
b Peers

6. Do you believe a person is intelligent because of:
a Environment
b Genes
c Peer influence

Once I have been given a safe planet, an atmosphere and animals and plants I can consume, everything else is gravy.

The incredible ingratitude of being given all of that and saying "but I want a meaningless merit badge too!"

Get over it.

Why is life soo unfair?

Why is life so unfair. Why is it those people that make others feel horrible about themselves, that fake a lot of things, that are cocky, are the ones that make it to the top and always seem to be getting the best out of life? Why? These are some of the things that sometimes make one think there's no God, I mean, clearly if there was a God, He'd see to it there is fairness amongst people. He's answer people's prayers. He'd here the voices of the sick and do something. Why is it that the world is so cruel? Why is it that we have no choice of whether or not we want to live in this world? . I know "life is what you make it", but stuff it, sometimes things happen to you that you just can't easily brush off, paste a smile on your face and be all optimistic. Is there an answer though? Does anyone else agree? sometimes I think even the universe favours some people and forgets the others.