How do I calm down my "excitement" towards my boyfriend?

You cant. Your hormones are raging. the only thing that I can advise is that you two not be alone with one another until you are ready for the next step or until you learn to keep your hands and mouths to yourselves (not saying you guys havent) because its obvious that neither of you can control yourselves. Doing sexual acts (i,e oral, mutual masturbation, dry humping, etc) will only make you want each other more. So try to have some one in the room with you guys so you wont be tempted to do anything that will make you "excited"