What bill.prag said.
I'd change 1 character in my master right away and regain control of the account. Please don't attempt it without understanding if that confused you but you need to protect yourself. Save it to paper. Once my master is secure again on paper only I have my account back.
Then change each key one by one, 1 character, then figure out whatever you did in the past that gave someone access to your private key.
Don't do that again.