I concur with some of the others - too much on your plate.
I found it hard enough to stay motivated on my one project, let alone four. Even on one it can be overwhelming and it feels like you'll never get done. But, by making time to do something every day (or when you can) helps get things scratched off the "to do" list. They do feel like accomplishments and do make you feel better about progress.
My best friend has about four going on. He's in his mid 50's and is running out of time (meaning you can't crawl around these things forever). Yet, he's getting nowhere because all he sees is how "impossible" it is to get them all done. He's experiencing gridlock, and may not get out. He wants them all so bad he can't let go of any of them. But, if he is to have any chance of finishing any of them, he must let go of the rest.
My advice to him and you is to focus on one and hope you manage to get to the others before you're too old to do so. Focusing on one, and striving for little daily goals will get you there. I'm sadly sure my buddy won't get his done, but you may be able to.