Oh my... I understand that you are feeling a little sad at the moment but if you make others feel miserable you wont ever feel better and you will continue on a negitive spiral which will be harder to get out of.
I am sure that deep down inside of you, you are a good person. we all feel a little sad at times but taking it out on others will not make things better.
If you want things to improve in your life then you just need to change your attitude towards life. It is quite simple once you know how. Smile at others, make a new friend, give some money to the homeless, try and make others around you feel that they are important, the possibilities are endless ^_^
You must remember: If you want to have a good life then you must take it upon yourself and make your life how you want it to be. It is up to you if you lead a good life ^_^
I hope that I have helped you, even if it is just a little. I am sure you will be fine in the end : )