I seem to have lost my account credentials except for my username, and I am furious. So, I clicked on "Lost Password" and it redirected me to a message that said "Check your email for a message sent". So I checked my email and it wasn't there. I went on the Steam Support website to enter a question. I waited a day or so, and I still didn't get the email. I'm angry!
Do you mean you don't remember your password. In that case either you used an old email-address when you started the account or it's in your spambox.