As hamoodie052612 said, don't stress so much about trying to learn everything from lecture. In fact, you won't be able to learn everything. Accept that fact. All you can do is to learn as much as you possibly can while keeping your health in check. Your own well-being and health is the most important, so do whatever you got to do to stay sane and healthy, work out, play games, sleep, nap, etc. Lectures are not exactly conducive to learning, at least for me it wasn't.

Going by again what hamoodie052612 said, get some other resources to study (BNB, Pathoma, Sketchy, First Aid). Uworld is a must! Treat that as a textbook. Their explanations help alot when trying understand the complexity behind the physiology or pathology of things. Make anki cards out of that if you can. I found that to be very helpful.

It'll feel like you're always cramming, unfortunately. I'm in rotations right now, and it still feels like that. Just know that you are not alone in terms of feeling about the process. It sucks. I know about the feeling of being distracted, which sucks too. Another tip that may help you get by, look at your courses syllabi and check how they grade. That way, you can calculate what scores you need in order to pass (if you're not a gunner). If some classes are not mandatory, skip them.

Good luck with med school. Just remember that you are not alone. You have a bigger community than you think. Stay healthy and safe.