Students often want to know the answer to this type of question, and I can understand why. Unfortunately, there is not enough information to give you an accurate answer. You would have to know which system your teacher was using — a simple average, weighted average, or point-based system. Then you would have to know the scores on all of your assignments and their points or weights, not just your current grade.
Your best bet is to talk to your teacher. Even when teachers seem intimidating to talk to, most of them want their students to succeed. In addition to telling you your grade, your teacher may have some ideas on how you can improve your school work.