Ignore people who tell you that you can't. People will try to rain on your parade because they have no parade of their own. If you have nothing nice to say about someone, say nothing. Advice from your mother. Forgive and go forward.
Grudges block the positive.
Until you clear the past, you are destined to repeat it. Look at any athlete. Self-talk is a crucial part of turning expectation into reality. That is what you will become. Spend 15 minutes a day focusing on a positive picture.