I'm currently in the process of writing a song. I've got a tune and I'm putting the lyrics together but I'm always concerned that any tune I think of might just be another song I've heard somewhere randomly that I don't remember hearing.
Do I just have a shitty memory or is this a problem that other people have too?
Don't worry about it. There are only so many progressions. Everything else is just variations within them, with bass lines, melodies and rhythms.