You need positive thoughts to have a Positive attitude.

There is certainly more to a positive attitude than first meets the eye. For by having a positive attitude you suddenly find most of the following benefits, and they become part of you, and you, and without thinking, beautiful things begin to happen.
Take note of these right now, for when you begin to get the idea of positive thinking ,these are your rewards.
You have to say to yourself, each of them is what I want and what I need.
Positive thinking, Constructive thinking.

Creative thinking, Expecting success.

Optimism, Motivation to accomplish your goals.

Being inspired.Choosing happiness.

Not giving up. Looking at failure and problems as blessings in disguise.

Believing in yourself and in your abilities. Displaying self-esteem and confidence.

Looking for solutions. Seeing opportunities.
Take each of these and begin working on them. I would suggest you download "Think and Grow Rich" Napoleon Hill's wonderful book.
Click Here for the download.
I personally have read this book, most likely close to one hundred times, each time I just cannot put the book down. I suggest you visit http://befinanciallyhappy.com there I tell a little story which I am sure you will enjoy.
As an uneducated man, I am pleased to tell you that I have had a pretty successful life, not just in the business world, but in marriage and with family. I assure you being positive is far far better than having those negative thoughts that were forever with me when I was young.
Please take another look at the list above and go over each of them carefully, for each has a message you should investigate.
Once you have that positive attitude your life will never be the same again.