If the letter count is correct as (3,4,7) for "Don't worry about me" then I'm afraid I wouldn't get it even if I waited until June as I've been through my list of number one US and UK singles from 1950-80 in US and 1952-80 in UK (all charts) and i can't see anything.
I sorted alphabetically and looked for anything starting with I'll, It's, I've, You, For and The; then I went through the whole list. Last word could be Alright but that drew a blank.
I even wondered if it could Hey Jude (NaaNaNa).
I also wondered if it could be the incorrect title I've Been Waiting (For a Girl Like You) by Foreigner (waiting for a girl like you), but that was 1981.
So I'll just wait and see if anyone comes up with an answer