It doesn't change if you hold it, it will continue with the same amount, but the value doesn't change.

Please help me!
I had almost 500 Reais in ETH, which represented 0.20 of ETH,
now the market is falling and my 500 Reais are simply 270 Reais, but my tokens also fell, I don't have 0.20 ETH, is that normal?
shouldn't I have the same amount of Tokens?
Because I imagined that nothing would change the amount of Tokens.
I thought that, if I have so many Tokens at a certain value, if their value decreases I lose, if it increases I profit, but the amount of Tokens shouldn't change, right?