Angry and I know it

Don't fight your anger. It's got something important to tell you if you'll honour it by listening. You are never wrong for feeling angry and no one can tell you when anger is valid; it depends on your personal values. What we usually struggle with is manifesting that anger constructively. Anger serves to push you to make a change for the better in your life, your job, your relationships, your well-being... It's not an excuse to rant, rage and act resentful. An emotion is uncontrollable but your response is your responsibility. 

At some point you'll have to stop blaming the things you said or did on mercury being in powerade.. :) You don't need to make excuses for your anger if you honour yourself and respect others. 

But respecting others is about HOW you express your anger, it is not about stuffing it inside and only allowing it to come out in small, bitter doses of passive aggressiveness. You're entitled to your feelings and you are allowed to set limits on how the world interacts with you and how you will respond in return.