How to deal with lots of information as a Computer Science student?
It is hard to diagnose a problem at a distance and I'm not sure I have a good sense of the core issues, but one thing seems to stand out in your post. I wonder if you are trying to treat every fact and bullet point as of equal weight, value, and importance. That normally isn't true, even in technical subjects like CS. A good lecturer will come to class with a few (about 3) important points that need to be made. Everything else will support those. You want to walk away from the class knowing what those are. 

Of course, some professors will walk in with a big powerpoint deck and just run through the slides as if they are all important. Those lectures may sound good, but a more focused approach would be better for them and for you. You can't affect that, of course. But if it is possible for you to do it, try to get the professor to distribute those slides prior to class. My strong advice is to print them out on paper, maybe 2-up or 4-up, and take notes directly on the printed slides. No more than a few words per slide. Don't try to capture every word. 

I also wonder what you mean by "summarizing" your notes. Some people would, again, mean trying to capture every thought. Capturing them by typing them isn't actually very effective in getting it into your brain, as opposed to your computer. What you want is to distill the notes into the few key ideas that make the rest of it easier to grasp. 

However, don't neglect to do the assigned exercises. That is where real learning occurs. Focus especially on the assignments. 



If your university/professor permits, it might be worth forming a study group with some (three or four) of the other students. Get together a few times a week and exchange ideas about what is important and also ideas about how to learn the stuff.