Try to start writing some of your own stuff, if you haven't already. I know it may seem impossible at this point, you might seem overwhelmed with the idea (if you have never written music before), but with practice, it will become much easier. Start off by just choosing 3-4 chords in the key of C (chords in the key of C are: C, D minor, E minor, F, G, A minor, B diminished) and strum them repeatedly and try to come up with a vocal melody to which lyrics will be sung. The lyrics can be created later, I find it easier to come up with a melody first, and do the lyrics later. But that's just me. Another thing you can do is instead of just strumming chords over and over, arpeggiate them and see what kinds of cool melodies you can come up with. Gl.