BladeRunner,
As I understand dysthymia its a sort of chronic low grade clinical depression (please someone correct me if I'm wrong) but from your description it seems to me your depression is worsening or changing and it would be a good idea to see a GP who might possibly alter or change your medication if its felt necessary. Counselling in conjunction with rest and medication is often a good idea. Your description of a bottle with holes in it isnt one I've heard before but it really does describe the feeling perfectly.
The horrible tiredness is a very common symptom as well as no interest in things you would normally enjoy, as is feeling guilty that you cant do all the things you feel you ought to do.
In my case stress does definitely bring on depressive episodes so it ay be the same with you.
You might find his little book some help, Depressive Illness - The Curse of The Strong, (yes lol I definitely think its time I started asking for commission on its sales!), I found it very helpful and I think several others have too, there is a web page with extracts from the book too you might want to take a look at