Ahah me too, I don't know what I buy xD I think as long as there is communication then that's fine, like you said sometimes we just feel we can't draw at all. Once I bought something from an artist and waited several months before sending a note... with no answer. I resent a note almost one year after the payment to ask for the drawing or at least a refund (which is what I got at the end).
I understand ahah I'm feeling really guilty when I take too much time too, this is extremely stressful for me,, that's pretty much the same for me, I can take 1-2 week to one month if I don't enjoy at all what I have to draw. I'm pretty lazy too- xD