Yes, I guess fake websites which look a lot the same are actually the biggest problem people have in the world of cryptocurrencies. We have to be very attentive on the links we use. Yet I don't understand why did the op give private key at all.. Aren't you like supposed not to give it even to the most legit-looking people? Or was it just entering the key on a wrong website? I guess this is more explainable. It is very unfortunate the OP lost all assets from that wallet.
If you really lost a lot you might try to find out more about the email address and try creating a complaint of FBI website but this is not likely to help a lot as well...