Feeling guilty for experiencing happiness after a loss is a form of survivor's guilt. You might feel like being happy means you're forgetting them or that you don't care about their death. This guilt is misplaced. The person you lost would likely want you to find moments of joy and to continue living fully. Happiness doesn't diminish your love for them or the significance of your loss. These moments of lightness are actually part of healing and can coexist with your grief. Allow yourself to feel joy when it comes naturally.
Grief & Loss
Why do I feel guilty for having moments of happiness after someone died?
Survivor's guilt is common in grief; feeling happy doesn't dishonor the deceased, and they would likely want you to find joy again.