Consider ... negative emotion = energy in motion (Amit A Desai). The tough part of this realization is, rather than ignore or avoid that negative emotion (which only enables it to get stuck within you), let the negative emotion be felt fully and flow through/beyond you.
I was thinking that living in the NOW moment meant not giving power to negative emotions from the past, but belief was vanquished by "The Art of Allowing ~ Explained" (Desai) and discussions with my friends.
If the feelings surface for you in any moment, that is the time to deal with them. Feel them. Sit with them. Give them voice. Like the whinny child, they may just need to be heard fully. Ask yourself questions, to try to go deeper and deeper into the feelings.