My question is:
Why did you sell your coins when the price is down?
Do you panic because the price is going down at the time and you did panic selling?
actually this very usual and common to happen in most traders, especially beginners or someone who only follow the hype and FOMO.
That is why it is better to learn first about trading before entering.
Many people only follow the hype to buy certain coins because of FOMO. However, basically, they don't know how the market works or how altcoins. Many altcoins are very volatile the market is not stable. That is why it is very normal to go and up in the significant time for certain altcoins.

I suggest you learn more about trading and also seek the information about the coins that you already bought. Never panic selling when the price is going down, keep calm and look for the news that happens. I suggest you also choose top coins at first.