Monero isn't overpriced. There is very low probability to go down. And if a dump was there would be only chance to buy more moneros as Aminorex said.
And at Polo only BTC,ETH and XMR have trading pairs with another alts. It means that Monero isn't on bubble.
Actually this altcoins bubble provoked by not smart new Japan investors. -->https://medium.com/@coin_and_peace/new-wave-of-japanese-investors-are-fueling-the-great-altcoin-bubble-a504383172ff