I would echo that getting involved at church is important, but I don’t think you must find a “small” parish. I belong to a huge parish in the burbs that is basically many smaller circles that intersect within the larger parish. We still have the ability to get to know many people on a close level while having the resources to pull together almost anything because of our overall numbers.
I like it that we have groups for young adults and for teens and for young mothers, etc. There are also things like choir or Bible study or the annual parish carnival that always involve people from every age group and station in life. Only you will know what is comfortable for your situation and your time in life.
My most important advice for you is based on personal experience. I moved to Texas about 10 years ago and I did not get involved right away in the church or the community. I only knew one person other than my coworkers for the first few years. It made me more depressed to sit in my apartment or to usually go to movies and things alone.
Chicago has a long Catholic tradition, so you should not have any trouble finding a place that is appropriate to your needs. There is likely a large Catholic singles group either through the diocese or through some of the parishes.
There are also so many things to do in the community that you can surely find something you like to do outside of your future parish. I have organized softball and volleyball teams with coworkers and through churches. There are cycling and running groups in Chicago as well as ways to get involved in the arts if that is something you like. Our art museum does a happy hour with jazz music on Thursdays that brings out lots of single professionals.
Just make sure that you get out and do something outside of work! Don’t let yourself miss all of the great opportunities by sitting at home and wishing that you could hang out with your family.