Feeling Very Sad Tonight

I'm not sure what's driving this mood tonight.  I know I have to go back to work on Monday, and I'm thinking that I should have done a little more work than I did over the break.  I had a list of things to do today and did the important one, but feel I should have done more.  I'm also very tired which is why I haven't gotten more work done.  So, I have a couple of should statements driving my mood, but is there anything driving the should statements?  I did do some work over the break, which is more than I needed to because I'm on vacation.  I had plans to work on a paper over the break but didn't get around to it.  It's really not that  bad, but when I look forward I think that I will be swamped on my return.  Regarding the other things I planned to do today, it's a similar situation.  I think that putting them off until tomorrow is just going to fill my tomorrow with more stuff I can't complete.  In both cases I'm forecasting catastrophe.  This is typical of me and may be related to my tendency toward black and white thinking.  Either things will be good or they will be bad.  The trouble with that is when something is a little off I forecast that it will be very bad.  I got something major off my plate today which is a very good thing and now I am tired.  The only thing I should do is get some sleep.  Things often look better when I'm rested and looking at them with a fresh mind.  I'm feeling a little better now.