Monday morning dread

I'm laying in bed awake at 4 am, dreading going in to the lab today because I've fallen behind schedule again and don't want to admit it to my PI, who will be expecting an update.  It's been about 3 weeks since we last spoke, and I've only managed to write about 450 words in that time. I'm not sure why this always seems to happen...whether it's my neuroses or his added pressure or some combination thereof, but I feel the need to make excuses for my lack of progress. I haven't been depressed, per se...it's more of an anxiety about moving into uncharted territory:  I've never written a discussion section before. And lots of personal stressors have had me completely distracted and unable to focus on my work...so maybe I'll just blame the ADD...but then why don't the anxiolytics and stimulants help?  I even tried Hemingway's advice to "write drunk; edit sober" a couple of days last week...that's how I managed the 450 words I did get drafted.  So not only am I ashamed of this lack of progress, I'm also doubting whether I'll be able to finish the rest of my dissertation by the late-January deadline. Hence, my desire to hide under the covers and stay in denial & avoidance mode. :-(