u/LucasDaOnlyOne781

This is my first post here, sorry if this isn't the place. I'm basically new to songwriting, but I have studied a bit of music theory. I managed to put up what I believe is a good chord progression, but I can't manage to find something good to play in order to introduce the said progression and have a loop. I was aiming to make some sort of sad song, but none of my solutions are near to good. Can someone help me with a suggestion or two?

This is my progression:

Dbmaj7

Db7

Gb

Gbm