Science Lab Aid...w/o a teacher (?)

Hi, I teach 30 minute blocks of science to grades K-2. I have my own designated room which is connected to library. However, I do all the lesson plans, experiments, etc.. This is my 7th year. Someone told me that because I teach a "class" w/o actually aiding a teacher, that I should be compensated in higher pay scale. Is there anyone out there who teaches a class whether computer, art, music or science lab....that is the actual "teacher"... And what are the laws regarding this? What group do we fall under? I love my job!!! Even though I teach over 600 children a week. Have a Happy Day!