Heart beats way too fast, panic attacks?

when ever I go to school, my heart rate goes way up. The reason is Im stressed ill have to talk in front of the cl and just the anticipation drives me crazy, my heart is about to explode and my throat goes dry. Im just so afraid to ridicule myself in front of everyone its almost a phobia now. it wasnt the case last semester but this semester is intense. Any thing i can do to alleviate my situation? thanks