Saving baby orange tree

My little citrus trees had quite the journey while moving. They moved to my parents' house back in the end of March. Once it got warm enough, my mom moved them outside. The lemon tree grew a bunch of new leaves there. Then, after our wedding, my husband's parents took them to their house. Then they brought them here on July 3rd.

The little orange tree was in bad shape! The leaves were yellowing, and over the next few days they got way worse even though I repotted them immediately into some fresh citrus soil. Then, three of the 13 leaves fell off. I knew something was wrong.