Well it's really good that you care about your hobbies. Education needs hobbies as well! It keeps your mind fresh and energized. But you need to put priorities. When you accept or find yourself with heavier work, means heavier responsibility, and you must respond to this responsibility in a positive way.
The first thing you must do for managing time is to reduce your hobbies. It's difficult but you have to. If you do not do that, you'll fail to manage the time no matter how hard you try. Right now you have one priority. Finalize your education year with acceptable results. And by your description i can tell you have lots of things to make done.
Keep the most effective hobbies one or two. Then remove the rest out of your daily life. Put the time and effort on your assignments.
Be organized (no ramble anymore) set up your day's plan each day by the morning (an exact plan). Sleep on time and wake up on time (sleep max 10 PM wake up max 8 AM) reduce your hobbies (keep one or two the most effective ones). Put more time on education (focus) be on time (do what you planed to do, don't send today's job to tomorrow) make sure to always have a clock with you (be aware of the time) split your study and researches into positive sides. (so important, almost important and not that important) first study or do very important subjects and follow the order. This way you win. Even if you don't get enough time to study or research everything. You already got the most important points so you'll get higher chance at the end.