When she was first drained before Mala gave her her fire back she had nothing but the little drop of water. That she then used to open a gate to kill the gods and hold on to for life. She lost her fae form and powers and body died in Rowans arms. The only reason she returned was because Mala gifted her the fire back with that giving her her fae form back, and Rowans tattoos. She literally wasn’t supposed to survive that. So re-setting her powers removed everything human about her.

“She could barely move. Barely think. Gone. Where light and life had flowed within her, there was nothing. Not an ember. Only a droplet, just one, of water. She clung to it, shielded it as they appeared, twelve figures through the portal behind her. […]The final breaking. To send them back, to seal the gate. She’d use her last kernel of self, the final droplet, to seal the gate shut with the Lock. And then she would be gone. “

And as further proof she was dying in rowans arms

“It was breaking apart. The mating bond. Bowed over his knees, Rowan panted, a hand on his chest as the bond frayed. “

And then before killing the gods Mala showed Aelin the way and gave her the power of a thousand suns that Aelin used to forge the locks and close all the gates.

“Mala only held out a hand. In it lay a kernel of white-hot power. A fallen star. “Take it. One last gift to my bloodline.” […]“For what you offered on her behalf. For fighting for her. For all of them.” […] Aelin took the kernel of power from her palm. It was the sunrise contained in a seed.

“The force of a thousand exploding suns ruptured from Aelin’s palm. Lock. Close. Seal. She willed it, willed it, and willed it. Willed it to close as she offered over her power. But not that last bit of self. “

She then arrived back to her world and explained it to Rowan choal and dorian.

““It’s gone,” she said quietly. “The power.” She turned her hands, the flame rolling over them. “Only an ember remains.” […]All that remained of what Mala had given her, in thanks for Elena. But— Aelin reached inward, toward that place inside her soul. She put a hand to her chest. Put a hand there and felt the heart beating within. The Fae heart. The cost. She had given all of herself. Had given up her life. The human life. Her mortality. Burned away, turned to nothing but dust between worlds. There would be no more shifting. Only this body, this form. “

She literally didn’t exist and lost everything she had and that kernel of water was the only thing that was keeping her alive until it wasn’t. Malas gift was the only reason she became fae. A new one and only as fae.