I'm not a big fan of daily goals, I'd rather hit a monthly target. The reason for this is you never know how the rest of the day will go. There could be news that will provide a substantial profiting opportunity which can help offset some of those losing days.
Ifyou get to a point in the day where you are comfortable with the profit, then cut your size in half, and keep trading. But don't allow yourself to lose more then 20 - 30% of your closed P&L. This way you will build confidence in trading at all times during the day.
Same thing when your losing, instead of stopping, cut your size in half, and in half again if you keep losing. This way, if you get to a point in the day where things start to work, you can resize back to your original size, and potentially make back your losses, or even go positive. At a minimum the smaller size trades won't aggrevate your losses too much further.
There have been many days where I've wanted to leave cause I've made more then my avg daily P&L, but was ahppy I stayed cause I made alot more. Even on the days where things just went dead, I managed to keep the majority of that profit. But it helped me alot to stay and learn how to trade at lunch, through sideways markets, and through big reversals.