I suggested last week, that when you sense that you are getting into a downward spiral, that is the time to redirect yourself. Do you need to reframe? Perhaps an option is to say, "writing has been hard for me lately, and yet I'm almost done with my first draft." Or, writing has been hard, but at least I am persevering. For me at least, that kind of statement gives me a little lift, which I think puts me in a better position to write.
Or perhaps I need to encourage myself... remind myself of times when I have felt good about my writing, when the process has been a little easier (this can also have good information -- for example, when doing this recently, I realized that I wasn't approaching my writing in the same way. I typically need to do something away from the computer ((walk the dog, fold laundry,etc)) , and just play with ideas in my head). Then once I have the first paragraph set, I sit down to write and it usually flows for awhile. I wasn't doing this, I was just sitting down and trying to start in front of the computer.
Later this week, I'll post two more strategies for redirecting negative self talk.
Cheering you on in your work!
Harriet