Lost my retainer and teeth moved what should will happen? HELP?

I got them off in Jan, and wore the retainers every hour, then my dad threw them out three days ago, and I see a small gap between my teeth and notice it when flossing, I also go to a dental school so appt. tend to be far away, my check up is oct. 14 What are my options to close the gap? can they adjust the new retainers w/o getting braces again because I know molds are not kept