That concept has already been discussed more than years ago, and even when the price was less than $250 everybody was saying that it was a bubble because it came from $1 to $100 in a few years.
So no, there is nothing to be worried about.
This bubble issue is the oldest and most argumentative issue of all time in Cryptocurrencies. Lots of the most respectable personalities in the world says that "Bitcoin is a bubble" but now they make themselves regret. As long as many people are supporting this coin it will never be a bubble.
Bitcoin in itself is not a bubble but no matter the asset there is the possibility of bubbles forming, a bubble is just an extreme overvaluation of a good, that is all, that is what happened with real estate a few years ago, real estate is not a bubble since we all need houses to live in and places to work and places to have some recreation but too much money was poured into it and this created a bubble, bitcoin follows that same principle and we should never forget it.
People are keep on saying that bitcoin is a bubble, yes the price are quiet high and the demand for this are pretty impressive but we must also understand why people are keep on investing on bitcoin which offers great technology. This is just a correction right now which is very normal on every market, well if bitcoin are real bubble I will keep on investing at a dump price for sure.