Definitely stop using that wallet and create a new one. Someone has your private key, so anything you put in that wallet they can take out.
If you still have any coins in the wallet, then move them somewhere else as quickly as you can, or they might also disappear.
Also never enter your private key anywhere, no-one ever genuinely needs to ask for it. I suspect you must have entered your private key on a fake airdrop - some of them do sometimes ask for it, which is a sure sign that it's fake.