This was the third consecutive night that Frodo had suffered a nightmare-ridden sleep. No matter how long he spent trying to clear his mind, the nightmares always came, and they were always the same.
He was running through a black, forsaken land. There were circles of fire throughout, but the fire did nothing to illuminate the area, and he thus found himself stumbling over many obstacles. All the while a voice beckoned from afar. "Come to me," it said, "and I shall put an end to all your woes." But all the same Frodo kept running, and the voice grew more menacing, spewing out threats that Frodo forgot upon waking. Frodo felt his mind being torn to pieces as the distant voice penetrated his mind and made his memories decay until nothing was left.
Frodo longed to wake himself up before his dream self's memories faded, but he could not force himself into consciousness. So he slept and awoke completely drained, and his energy suffered because of it.
He was dusting his study when a sudden, highly powerful desire to claim the Ring assaulted him. Whatever reason he might have had, whatever sense of "the Ring is gone and it cannot be claimed anymore," abandoned him, and panic took hold when he searched in vain for his destroyed treasure. As a last resort, he groped for the chain around his neck, and as his fingers found the gem that Arwen gave him, calm set in, and he sank to the floor as his meager strength emptied.
He hadn't felt this weak since Mordor, and it frightened him greatly. He had been doing so well this summer, so well that he dared to hope that he was starting to heal, but all that was lost. If anything, he felt worse than ever.
He was startled back into reality when he heard a knock from the door. "Come in," he called, still too weak to stand up and answer the door himself.