Loss is a part of business. I hold my coins when they are in loss if I believe in the project.
There a lot of ways to deal with loss; if I loss small amount of money, I will just rest for a while a try it again, as what others said: try and try until you become successful. To have a loss is normal, just deal with it positively.
There is nothing new in making some investments and going in loss. This is a part of life. To appreciate and enjoy profit, one needs to go through losses to understand the importance of profits. Indeed, if there is small loss which is easy to bear, everyone would try to take some rest or will try to divert mind but if the loss is quite large, it is advisable to not repeat the same mistake rather do good research for the cause of loss.