I got this info from @someguy123 who created an EOS-in-a-box post a few weeks back, but I bet there are a lot of people who want to check to make sure that their Ethereum wallet address is registered to the EOS blockchain.
Here's the website you can enter either your Ethereum Public address or your EOS Public address and see what your account name is: https://eosio.github.io/genesis/tools/account-name/index.html
It's very difficult to find this page anywhere on the internet with searches, so thanks to @someguy123 for providing that. It might be good to bookmark this site.
It's safe to say that if nothing comes up, then you need to register your Ethereum address to the EOS chain. @sandwich has a good tutorial on that. I will get that for you shortly: https://steemit.com/eos/@sandwich/the-most-important-eos-public-key-to-an-ethereum-address
pro-tip: DO NOT ENTER YOUR PRIVATE KEYS.
ONLY ENTER YOUR ETHEREUM PUBLIC KEY OR YOUR EOS PUBLIC KEY.