When you say that you teach 7 classes a day, are you actually the teacher of record for 7 classes? If you're assisting or team-teaching, make sure that's documented properly. Perhaps you're only the teacher of record for a few of those classes, so your administration thinks you're not that busy. Here again, could be ignorance, maybe they think you wont' question it, maybe they're willfully making you work more than they should. Be prepared, however, for them to tell you to take your conference/lunch during those classes that you're assisting because STAAR is more important.