I forgot my username and password for my netbank...

I have an online account and I have attempted to keep it for a very long time. Since I got it I have gone back to the bank three times to get a new username and password because I always end up loosing the paper and not remembering it.
Last week I went to the bank for the fourth time and they gave me a username and password, later in the night I changed one of them into something I could remember but I completely forgot to write it down. And now am stuck with not remembering again if it was the username or the password that I changed. And I cant remember into what name I changed it into :(

I don’t feel like going to the bank again like a fool and ask for another password and I don’t want them to think of me as irresponsible and stuff since I’ve gone there many times already….

what do you think I should do?