Hows It Going. Ill Get Right To It, Basically I

Hows it going. Ill get right to it, basically I work at fedex and i deal with boxes & packages. On the 23rd of October around 10pm i was under a (shoot);a metal runway that acts a a ramp to guide the boxes from the conveyor belt into the trailers about 10 ft high; as i was walking under it my manager was up top breaking a (jam);A jam occurs when there's an overload of boxes and someone must go up top and clear it: upon breaking the jam a 30-40lbs box came down and struck the back of my neck/head area. I believe i suffered a concussion after because i started acting strange. I felt dizzy, couldn't really catch my balnce, and a coworker actually asked whats wrong. Having that said i continued to work that night because we were short staff and have a deadline time limit to get everything done by 12:30 am. I clocked out of work around 1am. When i got home i had a roaring heading , took some advil and after a long struggle finally fell asleep. The following day i went to work to find myself with the same headache but this time my neck felt heavy, stiff, and most important sore. Long story short I was given the following week off to recovery but that time wasn't enough. After a week i finally went to a dr. My companies dr. i might add, and was told to return back to work. i still have a headache to this day. What should i do?