Things that help me ...

Get up after a nightmare and drink a glass of cold water

Deep breathing ... always

Call a support person if you need to - definitely call them the next day and
talk it out

Get out of bed and make a plan for the day - even if you don't feel like it

Journal (get the 'junk' out on paper, then look for the positive and write it
down because it IS there)

Watch something inspiring on YouTube - TED talks are good

Eat regularly and well

If symptoms persist, schedule a counseling appt. ASAP

Know this, too, shall pass. It always does

Try not to make too much out of one or two bad days/nights