Shit like this happens all the time with bands, a lot of song writers don't take the value of the other band members parts seriously..Just keep working on your music and mixing skills man.. You could keep in touch with your drummer, and the rest of the band and either work on writing your own lyrics or search for another vocalist. I hit impasses like this all the time even in hiphop, but I used to drum and do vocals for rock, and metal so I know how you feel.