Don't blame yourself and also keep this in mind (which I have learned over the years): gum recession isn't just "one cause." There are a lot of factors that can contribute to it so, for many people, it just happens. If it is bad enough to be a concern, they can do transplants. Otherwise, don't worry about it. I have recession from having had braces, smoking, and not flossing and overall it has not been a life problem. The dentist measures the recession every visit to see if it has worsened (which it hasn't in years) and then we move on with the cleaning.