Bit of a newb question here, but it has to do with selling my altcoins. So I bought Ethereum when it was $200, and now I want to sell it. Make a nice little profit there.

But wait! Now bitcoin has gone up to $3100. When I bought the ETH, Bitcoin was only at about $2500.

Am I losing anything? Am I gaining anything? Or has nothing changed? This one is a bit of a mind bender for me.