I finally went back to the Louvre today.
I've had a few days off painting, this doesn't mean I don't think about it and I've found out the importance of the fact to have an idea or goal for each session, specially the ones at the museum. If I do just try to draw a copy of whatever scene I get terribly lost in my process, and bored. Although it could be seen like exercising, I better have another goal more than that. Now, having that in mind it's much more motivating and I already feel like going back after tomorrow.
(I should take the time to set my scan right, light is a little strong and it tends to reduce the reds in some parts.)