(American & Canadian) last year using DNA tests, a helpful (and very determined daughter) and a bit of sleuthing. 
Is your mother still alive? If so has she requested her non-identifying info from the state she was adopted in? What are the cMs on your closest matches?
If you've only tested or put your data on Ancestry you might be missing someone that would offer a clue. My closest maternal were on 23andMe and My Heritage while my closest paternal were on Ancestry and My Heritage.
Have you downloaded your raw data and uploaded it to MyHeritage, Family Tree DNA and GEDmatch yet?
I'm not an expert but I'm always happy to try and help, especially adoptees (and their children). If you're on FB there are some very helpful adoptee friendly Genetic Genealogy groups I'd highly recommend too.
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