Looking for Biological Mom

My name is Margaret. I was born April 21st, 1996. Very late at night at MacNeal hospital in Illinois. My biological moms name at the time was Shannon Gallagher, she was 26 at the time and was also born in Illinois. I don't know my biological dads name, we have a guess; Chris O'Brien. I know I have at least 1 Aunt on Shannons side, who has maybe 4 kids of her own, all older than me, but not by much, just a couple of years. I've done Ancestry DNA and I'm going to be doing 23andMe in April (Getting it for my birthday) We were told that Shannon did not know she was pregnant, left very soon after I was born. Probably scared all to hell. At the time, she was into some rough things (Drugs, drinking) and thats why she probably didn't know. I was born extremely early, she probably wasn't even showing. I was very sick, maybe she thought I was going to die. I'm not sure. I think I've done everything I can, but still cannot find anyone, minus some distant cousins that don't have an idea on what to do. I'd love to get to know family members, see what they look like, share health information. What can I do to search more? Illinois law states I need to be 21 for records, but maybe I can do other things I haven't done, which will be surprising. I just cannot hire an investigator, I don't think I can afford one.