Set some time aside where you won't be disturbed. Have a notebook and a pen handy. Take a few breaths and allow your mind and body to relax into your meditation. Say a prayer if you like. Then allow your mind return to the scenario that is upsetting you, to the stressful events which occurred at that time. Use your notebook to write about it if that helps you.
Allow any emotions to just arise naturally. If a strong emotion arises, welcome it as an old friend. Welcome it as a beloved teacher. Sit with it a while. The mind often wants to tell us a story, but at this time, avoid that impulse and remain in bare awareness of the emotion. Be the witness. Do not try to rush or change anything.
If you sit with this difficult emotion or emotions – whether it is anger or sadness or whatever – it will begin to transform itself into its opposite. For anger the opposite is usually compassion, for sadness it is usually contentment or acceptance. As it transforms, this strong emotion will also usually reveal to you a secret, some bit of knowledge or wisdom that you have kept hidden from yourself.
Allow as much time as you need to feel complete. You may, however, need to repeat this exercise a few times to feel really finished with it. Also, be mindful of any signs or symbols which arise in your daily life or in your dreams which give you further insight into the situation.