since your wallet was protected with a password, it is unlikely that this theft is related to the vulnerability exposed last week.
In the other Version of Electrum 3.0.3 my bitcoins are still there (Friday night, after the alleged transfer !!!), my bitcoins are ok at this moment. After I opened in Electrum 3.0.5 all is lost, 3 days later.
you should definitely explain what you mean by that.
did 3.0.3 display a history where the theft transaction is missing?
is version 3.0.3 still installed on your machine?
if yes, please check the sha256 of the file you downloaded.
also, better stop using that computer and have it investigated by a security expert.