I forgot my password, and when I clicked I can't sign in. And when I entered my name, and everything, it says that it is going to send the verification code to this email that I is not mine, I even checked if I entered the correct user name, and it was correct. Is there anything I can do? Am I hacked?
You need to contact Steam support directly in order to recover your account.
Follow the instructions in the steam account recovery guide.
You will need proof of ownership, this can be for example one of the payment methods that were used to purchase games on the account. A full list is in the linked guide.
Also make a list of any previous account names and related email addresses that were registered to the account, all of that will help you get the account back.
PS: In the future you should consider adding extra security to your account, for example two factor authentication with steam guard on your cellphone.