Another good book to check out is Terry Brooks', "Sometimes the Magic Works: Lessons From a Writing Life." Excellent insights into the ups and downs of writing, from a man who has been through it all over the years.
When your characters aren't talking to you, it's okay to take a little time away. If you're anything like me, it won't be long before they're calling you back into their worlds. On the flip side, if you try to force the writing, and aren't really enjoying it, the odds are, the reader isn't going to enjoy it, either.
As to feeling like the latest draft you produced is trash? That's okay as well. That's why it's called a "draft." It's just like playing through a piece of music for the first time. Just as musicians practice and rehearse to work the bugs out of the performance, we writers revise and edit to work out the bugs in a manuscript. When we attend a concert, we are not seeing the musician perform the piece for the very first time ever. It might be the first public performance of a piece, but you can bet they've worked on it many times to get it ready for the concert. When we read a book, we should also not be reading the author's first draft (sadly, too often these days, we are). We should be reading the result of writing, setting aside, reading, revising, setting aside, reading, revising, and so on, until the manuscript is polished.
Finally, remember too, that our writing is a gift that God has given us. While using our gifts is intended to be a service to God, it's also supposed to be a joy to use them. However, there are also times when God wants us to step back from the service, and spend a bit more time with Him getting refreshed, so that our gift is also refreshed. That could be where you are right now - God may be using this "dry spell" to get you to take some of that time away from the writing to focus on Him a bit more.
After all, when we're dry, we happen to know the source of Living Water to quench that dryness.