I think it's clear that you made quite a bit of progress within those 3 weeks.
What I notice is, that your lines make the impression that you are quite tense. No need to hit the perfect line. I do like the imagery that was painted in one of the gesture drawing videos on Prokos Youtube: Imagine being a race car racing along the curves of the body.
I feel like you are a bit to focussed on detail here and there. You tend to draw in the muscles of the arms for example. What that tends to do is break the flow of the pose.
Another way I like to think about is: How can I make the longest possible line that still describes the pose?
Some examples:
They look pretty good in terms of proportions to me. What i don't like is your linework in some places, it looks a bit hesistant. Particularly for this exercise I think a bit more finish would help, there should be no ambiguity where a line is placed
Also it would be cool to add numbers to the drawings, makes it easier to track your progress (especially for us followers =)). Can't wait to see the next 7.
I can see some definitive improvement over the set, so all in all you are going in a good direction.
There's a couple of things I noticed:
To add onto what I wrote onto the image: No need to draw in the peak that's produced by the ribcage protruding. In my oppinion that's a detail that's hindering the flow. Nice long lines symbolize the stretching that takes place in that area, contrasted by the pinching on the back.
Also, while blocking out the major shapes is not an error, I personally find that it makes my gestures more stiff.
That being said, gestures are a great place to experiment. Try all kinds of different approaches and find out what works for you.