How long do I have to be married to get alimony?

We got married in Chicago 3 months ago and now I want a divorce. My husband became a different person after the wedding and I feel I don’t know him at all. I know we haven’t been married very long, but I did give up a very good career in Washington, D.C. to move here to live with him and get married. I can’t get the same kind of job here in Chicago as I had in D.C., and it’s too late to get my old job back. How long do you have to stay married to be eligible for alimony? I need financial help until I can find a new job and maybe even longer if I can’t find work that pays me an amount similar to what I earned before.