Deep breaths. There can certainly be surprising results from DNA testing but verify the facts thoroughly.
I'm certainly not a DNA testing expert, and I'm sure someone with more expertise will help guide you. But from the few facts you've posted, you'll just receive general guidance.
I will mention, my surname is not my "biological" surname. I've known this for decades and have avoided DNA testing until the generation that would be hurt by the facts has passed on.
From a WikiTree perspective, my "non biological" maiden name remains the same. It's what's on my birth certificate.
Good Luck with your research.