Having the right attitude is extremely important for your network success. I know because I have had problems with my own attitude. When you are negative and depressed, it is difficult to make good things happen. People will run away.
If you think you have a problem with negativity, you probably do. What has helped me understand my issues and see a way to change is positive psychology. Positive psychology finds what is right with people and helps you learn to be more positive and flourish.
Only about 20% of the population is naturally positive and resilient. Their studies lead them to believe that we can learn to be positive and flourish. You may want to keep your positive thinking books, but add some new ones backed by extensive studies and tests.
Unfortunately, most positive thinking seminars start wearing off as soon as you leave the seminar. The advice is not bad, if you can follow it. Few people do.
I will be exploring this area for myself. I am a work in progress.
Here are books I would start with.