MOSP. I know exactly how you feel. I am worried about taking on any commitments etc. because I can never be sure of what state I will be in on a particular day. In the end you do get frustrated because you know, deep inside, that you are more capable than how you have been functioning;it's just harder when it's been going on a long time.
I have managed to achieve small things (completing courses/passing exams) even though very often when attending I felt an absolute wreck, and it took me all the strength I could muster to even attend on a particular day.
mathanxiety - I know what you mean. You realise that, every day, you have been dealing with enormous crap, drudging around at the bottom of the pond, whilst other people are dealing with everyday stuff (most of the time;ok, everyone has problems), but, when you are dealing with consuming, negative stuff you get in some situations, you are permanently distracted, and miss out on just everyday life, let alone simply having a bit of lovely fun which lifts your spirits, and makes you realise there is more to life than STRUGGLING.
Breakfree-I'm glad you had some fun with your friend. Remember that feeling, how nice it made you feel, that your life can be more like this, rather than your mind being consumed with this stuff.