Yes trading is difficult. especially when the altcoins fall as you can get caught up in it. The value of your bitcoins may have fallen if you did not sell it immediately so it should be yours. And as you learn it you should always keep in touch with the news so that when there are good or bad news you can immediately answer it
Those are parts of the difficulties you have to face in trading. However, if you know what you are doing, you should always know the quickest and best time to always get out from a trade so as not to make a huge mistake hoping for it to get back past up. You can be lucky it goes deeper and you can buy then and profit back from the rise.