Someone that has your contact info has a spam Trogan or you posted your email info on an Internet board and a spam bot captured it. Did you check your email providers web email sent folder to see if the server saw the try sent?
Time you kids learn how use at leat two(2) email servers from different vendors. One for online shopping and one just for family or very close people. Maybe one for school email like the one your college gives you. Just remember to keep then seperate!