I recently discovered that I did not lose my German citizenship when my parents married and my mother and I migrated to the US back in 1948. How do I go about reclaiming German citizenship?

Not sure if you have found this already, but here is the official page dealing with citizenship questions.
https://www.bva.bund.de/EN/Services/...ship_node.html

This might be a good start. The forms to determine your status would have to be filled in in German.