This has happened to me twice now. It's because you exited the game during a full moon. It's a bug in the game they haven't worked out. Just take screen shots of zombies coming up during the day in the wrong phase and any other visible issues and report it to tech support. That brings it to the attention of the developers and they go into the game code, fix it, and then put out a patch. There's usually a patch for the bigger issues in games about a week or two after the release.
My advice for now, DON'T EXIT THE GAME DURING A FULL MOON. Wait until the game has progressed beyond that point, then leave. Or just turn off full moons on your unaffected saves until the patch comes out.
For the unchanging werewolf: testingcheatsenabled true, then CTRL + Click on the "instincts" moodlet. Once that is gone, you'll be able to change back into a human. The zombies will still be there for a bit, but at least you can get married! For your garden, you might want to use the new plant pots. I'm pretty sure they came SE, so you should be able to just go to collections, Supernatural, then scroll down. Place the pots in your house and put your plants inside. Your trees will still suffer because the game won't allow you to plant them in the pots, but at least most of your garden will be safe.