Asking teachers for help??

I understand that you don't want to bother him, but at the end of the days, he's a teacher. One of the roles of the teacher is to make sure that every student understands the subject content. That being said, come up to him and ask him when he'll be free and then say what you need to.

Say what you need. Explain that you're overwhelmed by the workload and you can't cope with it as well as others do. If he's kind, he'll understand. He'll probably talk to your other teachers and take it a bit easier on you. Don't worry, you'll get through it.