Losses can be different and the reaction to them should be different as well.
I try to differentiate the losses which were caused by some minot occasional fluctuations on the market and which are the indicators of some systimatic drawbacks in my trading strategy. In the first case, you just need to accept the idea that the market is still unpredictable despite all of the indicators and trading ideas that you use while making certain trading decisions. Such things happen all the time and they shouldn'r demotivate you. However, there are some losses which take place on the regular basis and this means that your trading strategy has some flaws. The only thing you can do is to analyze your past deals and point out the mistake which you keep making. That is why it is of utmost importance to make a trading diary where you can write all of the deals which you do.