S.,
I can be hard to be optimistic sometimes...especially when we have had a rough journey previously.
However, it is great that you recognize the need to think in a positive way...that is half begun right there!
Check out the Positive Mantras/Affirmations link from our Resources. Practicing this skill makes a huge difference in how we feel.
Keep us posted as to your progress as well...support is key!
S.C.