You could write stories in a song like way. After that, you could make a book about what you wanted the song to be if it was an actual story. Also, you can even do both. But whatever you choose tell me how to listen/read them :D.
And also, with your "very bad" singing voice, you can always take singing lessons. There are even some free videos on Y o u T u b e you can watch if you do not want to spend the money if you are not sure you are fully doing it. If you happen to come up with an idea for a book, jot it all down on paper. Then, you could start making a plot. After that, some characters (Btw, you don't have to do it all in this order). Then, to get a little more organized you could start writing dialogue. Just, make sure not to rush. If you happen to loose motivation, TAKE A BREAK! This is normal for people. You start to get burnt out and just want to take a break. If you don't choose to take a break, you will get frustrated and will scrap the whole idea. Once you've taken a break, (No matter how long it was, a week, a day, a few hours) if you feel like you want to come back to it, do it!
This goes for song writing as well. If you have an idea, keep a notebook with all of your ideas! But it's totally up to you. You could happen to enjoy one or another, do something totally different or mash them together.
Note: You do NOT have to do everything in this. This is just a recommendation from experience.
