Maybe a dumb question, but why after a long time of not following the same rate of growing BCH is dropping with BTC?

So we didn't grow as much as BTC did, but now we are dropping almost harder, it'a quite confusing for me.

And my anxiety is coming back, not a good signal, i don't want to panic, but this drop is quite crazy for me.

I'm a newbie, pls i need encouragement and information, i know as how cryptos works BCH is the most functional and that drive to invest on it's potential, but if it value depends on BTC then what's the point on trying to be a currency? Don't get me wrong but i'm anxious.

I just wanted to buy a new gpu with future money ?