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.
If you are in doubt try to buy other promising coins that you know you can get big gains. For now, the coin is fluctuating day by day it is better to HODL for now.