The trick I use is to measure my results by EV rather than actual result. This way every day is a positive day as long as you are playing positive EV. After a while you don't even pay attention to the small swings of a couple hundred units and in the end expectation and actual results will come back together, if you play enough.
Admittedly this technique don't work as well for me during extended swings. During a 5 week period in July and the first week of August I lost over 1300 units. It becomes a little harder to convince yourself that such a losing day was really a positive, because you played positive expectation game, when you suffer losing day after losing day for weeks at a time.