People buy lottery ticket all the time, thats total fine, spending $5 here and there for fun. But if you mortgage your house to buy lottery tickets you are crazy.
Same thing with bitcoin. Spend a few grand for chuckle is fine, chances are you wont see your money again. Heck I would pick up a few bitcoins too when it drops below $100.
If you spent your life savings buy Bitcoin, get out now while you still have something left! New crypto currencies are coming to replace BTC. Stop torment yourself everyday watching your money goes into red day after day after weeks after months.... you will spend your retirement working at McDonalds trying to earn it back!
Risking retirement in investing in bitcoin is not a good thing to do. You should have to allocate savings for yourself. Do not be deceived by the big earnings you can get. Think twice and make the right decision.