Honestly, Carol looking at Daryl and saying “I couldn’t lose you” - basically telling him she left because she couldn’t stand the thought of losing him, specifically - is such a romantic trope. She says she couldn’t lose her people, couldn’t lose any of them, and then the moment (probably) hangs in the air and she looks at him and says, “I couldn’t lose you”.
These types of moments always and only occur between two people who see each other in a romantic light.
Carol is saying that she loves everyone back home and she can’t lose them, and then she singles out Daryl, conveying that it applied especially to him. She loves all of him - but she loves him the most.