Crypto-currency is called that because the technology behind it is based on cryptographic functions to keep the system safe and honest, and to keep people from spending the digital money twice. Bitcoin was the first one that actually made it to relative fame, and made its first supporters millions. Of course, getting to the richess also means you have to be able to spend it some time, so the value of them is volatile, as people invest in it, and take out their winnings in order to actually do something useful with it.
This is only normal, and when you notice the swings, you have to think about the reasons for them. When my dad complains about having read that Bitcoin went down last week, I show him that over the past year it went down around 30% no less than six times, and each time it made a bigger recovery after that. On average, over 2017 the coin made 7 steps forward against 2 steps back every single time!
So yeah, I jumped in too, but did it the wrong way: rather than trusting my own judgment in buying and selling digital money, I trusted someone to be honest enough to do it for me. That worked out for a while, but only until the money became worth too much. I guess that is why they say: "If you want something done properly, you have to do it yourself!"
And so, I learned. Meanwhile I do use my technical knowledge of the concept to dive into the usage of Blockchain technology in my work, using the inherent security of digital currency and smart contracts to secure medical data.