Hmm. Interesting. I'm an outline-y person, so this usually doesn't happen to me, but it has on a minor scale. My advice, though doubt it's any good, is: just write. Don't think about how what your writing will affect the plot or if it doesn't fit the rest of the story; just put the first thing that pops into your head. 

You could also do what I just described, but don't make it connected to your amin story; just write a little fantasy of your own. like my "The moon is..." thread. I have one chapter of that story and I do know how it might go farther, but it was more for the sake of my "creative juices" than because I actually wanted to write a new story.

Well, whatever. I'm sure most of what I've said is useless; ot's just my opinion. Hope your story goes well! 

Bridge the metaphorical gap between where you are now and where you want to be in the story.

Wow. I'm sorry. Writers block is super annoying.

It sounds like you at least have some idea of what you want to write. If that's the case, just write. Don't worry about how it sounds, because you can go back and edit it later. In my experience, that's the best way to get creative juices flowing. 

I always seem to find that when I feel stuck on something in writing, the problem isn't actually where I'm caught, it can be up to a page back.

I was/am writing this madcap satirical-fantasy sort of piece where these four friends venture to an imagined world, the picture-perfect essence of a fairytale story... except everything isn't as pretty as it seems and wild shenanigans ensue.

At one point I made the mistake of having one of the main characters fall into a cursed, Sleeping Beauty-esque slumber. It seemed funny at the time (and I did get a couple good lines out of it— "What's wrong with him?" "I ask myself the same question every day.") but as I went on I kept getting stuck and frustrated and nothing was working suddenly. After a bit, I realized, oh man, I just knocked out the most interesting character in this stupid story for at least the next chapter, and THAT'S why I'm so stuck. So take a little read back, don't be afraid of rewriting, and try to figure out where you've gotten stuck!

And also? Don't worry if it sounds bad. Keep writing anyway. First drafts don't have to be good, they just have to exist. 

ooh, that sucks! I hate writer's block. Now, I'm not sure if this advice will help, but this is what I try to do.

reread the last paragraph or page to get a feeling of where you left off, (it seems like you've had this block for a little while now). go back to where you left off, and just write. Don't think about how it may sound. Don't think about how it will fit in with the story. Don't think if it's even written grammatically correctly. Just get words down on the page, and eventually you'll get back into the swing of things, and it may turn out that you really like you overcoming block writing, or you may change it completely. And that's fine! the point is to get over the block.

Hope this helps!