I am not self-employed but have a 1099-MISC (for a one-time job over a 6-month period) to file and I also missed the deadline? What do I do?

I did research work for a writer over the course of six months in 2015 and the amount of compensation was $672. However, I missed filing the 1099-MISC he sent me. 

Am I considered self-employed even though this job was a one-time thing? How do I file this late?