You're not sad, exactly. You're not happy either. You're just here. Going through the motions. Responding to things the way you're supposed to. Waiting to feel something again and not being sure when that happens.
Numb isn't the absence of feeling. It's what feeling too much for too long looks like from the inside. Your mind went quiet so you could catch up. That's not emptiness. That's protection.
But at some point the protection becomes the prison. And you can feel that too, the edges of it. That's what brought you here.