Dark Days

Do you ever have one of those days that just pop up outta nowhere and hit you?
That was Tuesday for me.
It should have been a great day. Monday, I had a job interview, followed by lunch/thesis prep with a good friend, dinner with my married friends, and a much needed catch up chat with a girlie I'd been missing.
I should have been flying high, busting out work on my thesis (I found out the first draft is due in March, not May, so I need to get my butt in gear!)
Instead, I woke up Tuesday morning and hit a wall. I couldn't drag myself out of bed for longer than a trip to the kitchen for snack. I was alternating between sleep and panic. I had received a call that I had a follow up interview on Wednesday, so I should have been stoked. Instead I was panicked, freaked out that the interviewers were going to think I'm not ready. I thought they might tell me I wasn't ready for the grown up job, that this was too difficult a job and too big of a commitment for me. 
I didn't pull myself out of bed and into the shower until well after 5 pm.  Even then, it was a challenge. If J. hadn't been texting me all day to check in on me, I probably never would have crawled out of my covers. I just didn't want to face the fact that I was completely alone in my world, with no human contact at all beyond my cell phone screen. 
Some days, I just can't handle being alone. I can't seem to deal with getting up and being responsible.
Some days, that's okay.
Luckily for me, as time goes on, these days get fewer and far between. 
Someday, maybe, I can avoid a dark day, alone in my bed with my Nutella and Wheat Thins for comfort.
Someday.
So, readers, I have a question for you.
Do you ever have dark days? If so, how do you handle them? Do you have any tried and true techniques to kick a funk and function? 
Please, email me if you have any tips, as I can use all the help I can get with this.