I've been going through a hard time, and I don't want things to be negative and sad any more. I completely aware that I'm in denial and I'm not happy but...

In your opinion what is worse?
To smile and say I'm happy
Or just be straight up not happy at all?

You should be honest with the people around you that care for you, tell them if your not happy and why your not happy. Don't put on a brave face and bottle it all up and don't pretend to be happy if your not, nobody is going to help you unless they know how your feeling inside. Everyone on earth is allowed let off some steam every now and again and everyone has a right to feel different emotions without being judged. And if there's certain things bothering you then you can always tell us. :) if your sad and you don't even know why, then chances are this is your hormones, or could be a chemical imbalance, so if your unhappiness lasts a long time for no apparent reason then you must seek help from a parent or adult you trust :)

I understand what it is like to be depressed and not want to drag other people down with it.
But there is a middle ground.
Don't talk about being depressed or unhappy in general because it goes nowhere. Try to find out what events in your young life are the cause, and talk about it with a best friend in private and a therapist if you can get one.
Go out with friends in groups and hang out, and just don't say anything unless someone wants to know why you aren't having 'fun.' Say that you are going though some things right now and would rather just be around them. There are many ways to say it that won't make them feel uncomfortable, because you aren't asking anything from them. Don't say things like ignore me or don't mind me because those sound self suffering and needy.
Good luck. Don't withdraw into yourself.

Tell Somebody How Your Really Feeling A Relitive or A Friend Some One Yout Close To Some One That Knows You Well.. See How It Goes From Then A Simple Thing Lyk That Could Make You Feel A lot Better..