I have some friends who bought in december 2017 at ATH. They had a lot of FOMO, and this is not good for investments.
I think that whoever do not have 1 BTC now but want to have it in the future should have patience. You do not need to get it now in the next 30 days. Nobody knows if BTC will be 30k or 5k in the next 30 days.
I believe the best for those moments is to keep the mind calm, buy the same value every month (in USD) and get as much as you can. You don't need to thrown yourself in ATH price because it is "your last chance".
FOMO is bad for investments.
"FOMO" should never be a reason to invest in anything. That pretty much means you are looking for a get rich scheme without looking into the investment at all. Those involved in Bitcoin know the volatile nature of it.