Misty Musco has the right idea with her comment. You should get an auDNA test. Also, you'd be surprised how much information you can get with a sealed birth certificate.
If you go to your state's or birth city's archives, you might be able to find your birth name or your birth surname, like I was able to do for my mother. Her birth certificate post-adoption actually had the same number as pre-adoption, so I went to the New York Public Library (biiiig library in Manhattan!) and went through the books for her birth year and found the numbers under CARRIER, FEMALE. When I found people later, through Ancestry, their getting their DNA tested confirmed they were family and that the name in the book matched the little information we had.
I truly wish you the best of luck. It's difficult, but it's doable.