Did I just get fired?

I started this particular job as a bank teller back in October of 2010. I started off as a permanent part-time employee until I planned on quitting and was offered a floater position, For those that do not know, a “floater” is a teller that travels from branch to branch to cover for regular employees that are on vacation or sick. I was a full-time floater for a summer and then I was able to transition to an on-call position. This enabled me to remain employed at the bank and work whenever I was able to, as I’m still in college. I was able to leave for months at a time and come work anytime I wanted to.

I am currently not working because I am doing an internship this Summer. I had plans to work two full-time weeks beginning in August before I start my final semester of school and then working Fridays on call until December, when I’m set to graduate. At that point, I planned on being on-call full time until I secured another position.

Today, I received this email from my boss:

“Hi Lyndsey,

I appreciate the time you gave us at [bank name]. It really helped us out.

Going forward, I just wanted to let you know that we will no longer be able to use you as an on call. I thought I’d better let you know because you had indicated you would be available to work some starting in August. We are only able to hold on to 2 on calls that have been working in remote branches where it is difficult to send regular floaters.

Hope school goes well for you. Should you ever consider returning on a more permanent basis, please let me know.”

This email kind of threw me for a loop. I just purchased a new car and was relying on the money I’d make working Fridays to pay that new bill. Now, it appears I’m unemployed. When asked why I left this job, what should I say?

I’ve never been let go from a job before and now I don’t even know what to do. Finding a job I can work on Fridays only will surely be impossible, but I can’t just not work until December and have this huge gap of unemployment on my resume. I was really hoping being at the bank for over 3 years would look good to my future employers. Now what?