You should obviously be moving any other coins on wallets from that scam site to a more secure wallet if you haven't already. But as you say and as discussed above, you made a lot of mistakes in your whole process, so I wouldn't trust any wallet you made that day (or any other day in which you followed the same steps).

It's fair to say at this point that it is not a bug but rather it is actively malicious. The owner was made aware of the issue, apparently removed it temporarily, and then reintroduced it. The malicious code is also years old at this point with hundreds of reports of people losing their coins. There is simply no way the owner is unaware of it. It continues to exist because he is actively scamming people.

This is part of the reason that I don't think anyone should use any website to generate wallets or private keys.