I received a check from Fidelity for my 401K but I didnt ask for it.

I worked at Starbucks up until the time that I started law school in August. While I was at Starbucks, I was contributing to my 401K each paycheck. Well, in December, I received a check from Fidelity as a cashout of my 401K. However, I did not request it and did not think anything was going to happen to it. So how do I reflect this on my taxes, or is it possible?