I am the queen of unfinished projects so I can relate. I get easily distracted from things I'm doing, especially if it's a tedious task. I've always been like that. Recently though (the last year), it also happens with things I enjoy doing.

An example from this weekend. Historically when I am working on a new website project, I can work on it for several hours straight. On Saturday, I started a project that has been on my list of things to do for several months. I did manage 4 hours on it and did well, and was happy with that. Yesterday, I tried to do the same, could only manage half an hour. I was very disappointed in myself. I couldn't get in the groove.

Anyway -- I can totally relate to starting something, getting distracted, then getting neither done.

I would recommend that you stay in therapy, but maybe explain to your therapist that the homework is distracting you from doing other things and is causing you distress. Maybe back off on the homework for a while, or decrease it?