Your seed was probably compromised when you generated it on a malicious website.
There are various ways to generate a seed safely.
If the transaction moving funds to an address that you don't own is confirmed: there is no "normal" way to get your funds back (and otherwise it would be a terrible flaw in IOTA design).
The only way to get your funds back is that the iota community agree to restore a snapshot anterior to the ofending transaction. This kind of event occurs once in the past when the whole community decide to authorize the transfer of all funds at risk due to adress re-use to a secure adress owned by the iota foundation (that's the the reason of the "reclaim" process).