Hey Laura, nice SB! :) But you need to update it more. I've gone too long between updates myself, though, LOL. I know what you mean about trying to balance academic stuff and drawing, not so easy sometimes. But I think you can do it. Are you planning on having drawing mainly as something for yourself, or are you interested in it as a career?
Anyway, on the to the drawings themselves. You are doing good studies here, keep it up! You need to work on you line quality a bit, though. You are a bit chicken-scratchy right now. It's easy to fall into that when you are trying to draw accurately, but you really want to make smooth confident strokes rather than hairy uncertain ones. It helps to use your whole arm to draw, and not just your wrist.
This sounds awkward, but I like way you draw boobs. :D A lot of guys fall into drawing pneumatic breasts, perhaps though a combination of A. not seeing real ones as much and B. unrealistic fantasy art portrayals of the female figure. I guess having real ones helps, LOL. One thing I'm noticing with your imagination figures above, though, is that the head is bigger in relation to the body than a real person. Are they children? It's a little confusing to me, and a bunch of your figures do not have those proportions so I'm not sure if that is what you are going for. Also in regards to anatomy, some of your figures have messed up proportions with their limbs. Watch out for that.
Anyway, you are making good progress so just keep it up! :) I'm looking forward to seeing more. Mistakes are the signposts to success so you are doing it right.