OK, when you create a new wallet with yoroi as explained earlier it will ask you to enter your passphrase!
Maybe you are typing the wrong passphrase in there. Please note that there will not be a “wrong” passphrase! Each passphrase you type here creates a seperate hidden wallet. So if you type a passphrase that is not linked with your wallet holding your ada it will show up zero ada because it is creating a new wallet.
Good chance your passphrase is blank. So just try to connect again with yoroi and dont put anything in the passphrase and just continue. does this help?