I can definitely relate to it, but perhaps in a slightly different way. I go through almost manic periods of creativity in which I am very happy. These happy times are followed by a phase of me forcing myself to be creative (and it does lift my mood, so I don't see this as a bad thing as I still manage to feel good), which is then followed by a period of feeling completely disillusioned and/or inadequate (which unfortunately, I am currently trying to get out of) and my paintings are left unfinished (though usually I do manage to finish them when my next round of creativity hits).
When I look at my own chart, I attribute this pattern/behaviour to having my Mars in the 12th House, squaring my Neptune, which is also my chart ruler. I am already not too energetic in general, but with the Neptune square, I also can become discouraged pretty quickly.
In your chart, I'd look at your 12th House also. You've got Saturn (structure, limitations) there which could indicate discouragement. Your Sun in the 1st House is a strong placement, but its opposition to Neptune can also attribute to discouragement.
Now, I am mentioning 'discouragement' as I'm not too sure how to interpret feeling 'ashamed' or 'guilty' about creative endeavours. Would you mind explaining this a little bit more?