I just want to be happy..

I'd try something new. Just get out there, maybe go for a hike or camping, or help out at a shelter. Animals will just make you feel in love all over again :D Maybe if you bring some new excitement, even if it's just temporary, you'll find yourself laughing again in no time :)

Start running. Use a bicycle, not a car. Don't smoke, don't eat chocolate, don't drink alcohol and caffeine. Live in simple way, don't be a consumerist idiot like everybody else. Read good books.

voulenteer ....at an old folks home , or local school reading,...i promise you will feel happy

I know my answer conflicts with the others at this point, but no-one can tell you how to be happy, you have to find it for yourself- if you like sewing or reading, do that. If you like shopping or watching TV, do that as well! It's all up to you (: If you think you feel empty because you have no aims or goals, set yourself something little each day, like finishing something you've been working on or bake cookies for a friend. Eventually you might find a little routine that stops you feeling empty and cheers you up too (: