I think it's good that your daughter is able to express her feelings to you ☺️ It's ok, her feelings are valid and emotions like sadness are normal naman po 🙂 Kahit ako kapag umaalis ang hubby ko ng matagalan, tinatanong nya ko kung ok lang ako, sinasabi ko na "ok lng sakin na umalis ka, i want you to enjoy, but it doesn't change the fact na nalulungkot ako kapag wala ka". I don't say it to make him feel bad or guilty, nalulungkot lang talaga ako. Hindi naman ako nagmumukmok, or nagiging disfunctional dahil sa lungkot, it's just what it is.
What I'm trying to say is that even as adults, we feel these emotions like sadness, and it's ok and it's valid. Over the years we have learned to manage it. So I think it's the same for your child who's just learning how to manage her emotions. Her feelings are valid and normal, try not to take it personally ☺️ As long as you don't think that she's harming herself due to sadness. Basta iacknowledge and validate mo lng ang feelings nya, and be there for her. The fact that she's able to freely express her feelings to you already makes me believe that you're doing great jobs as parents ☺️