Okay, an update:
I wanted to write 1670 words in the 5 marathon days and actually got 2532 (and didn't even write on Sunday)
I'm quite pleased with that.
And today I will go over 20K. That's only a sixth of the overall wordcount, but still, that's the first milestone for me.
I finally see some progress and and that's pushing me on. And where I only saw black in the plot and story, there's now some light grey and hopefully it will be all white not too long from now.
While I type away I get new ideas, and I'm already looking forward to working on them.
On another note: Carol talked about going crazy with having another WIP in her mind. And I so can relate. I have 4 (four!!) other WIPs in my mind (two of which will belong to the same universe as "Ella"). But I'm afraid - as Carol said too - that if I work on them also, I will have five uncompleted stories some time in the future and will never be able to finish one of them. So I let them stew and see what will become of them, when I'm at least finished with the first draft of "Ella".