why are all these cryptocurrencies are going down?
Most likely you are new to trading in general because if you understand trading you would know right away that correction is inevitable. If you bought on the peak price and sold it at the bottom then you need to rethink your strategy. Always have a game plan when doing a trade because if you do not have one you will lose not only 20% but 100% of your budget. Do more research about technical analysis or at least the very basic of candle sticks. Try to also research wave patterns.
Also be cool and do not be emotional this seems easier said than done but if you become emotionally unattached to your trading you will be a better trader.
Most people always panic at first when they are new to trading. However, it is always good to have a strategy.
Trading is more like; 'if this happens, I expect this to happen' and with that it would be so easy to make decisions on your trading without making too much huge loss and making some good profit. We have all been there but the good thing is to always be patient.