I entirely agree.
As for me, no matter how much homework and projects have been given, I seem to always have tons of spare time (resulting in quite a few overdue book reports and other assignments! That's due to my own carelessness though, which can be easily remedied. When it is remedied I would have a lot more spare time!).
At home, I also have a bunch of time-consuming hobbies -- composing music, writing novels, playing piano, watching anime, drawing manga, playing chess, etc. However, I always have time to do any of three listed above at any given time, maybe because of my lack of participation in extracurricular activities. From a rightist's point of view, I would live an okay school year. Here, they generally give about an hour of homework, which, for me, would be done in half an hour at most. They occasionally give hour-long or two-hour-long assignment too, but those are mostly culminating activities and assigned less often.
Not sure about your situation, but all the advice I can offer is this: if homework drags you down, considering giving up some of your lesser-liked extracurricular activities, but still keeping the ones most important to you (just don't have too much!). Or, tell the situation to your teacher if the above advice is not plausible. I'm sure the teacher will understand.
edited moderator AndrewSmith