"Because I didn't tell anyone," Spike answers the cat. It seems like a fairly obvious answer. The other answer is 'because nobody cared enough to check on me', But that's obviously wrong. Sunshine's here now, isn't she? Maybe a little late, but she's here.

He realizes, very belatedly, that's she's healing him. She's why he's not dead, not some miraculous recovery, just her. How long has she been doing that? Probably too long, if last time is anything to go by. He doesn't want her to injure herself trying to help him.

He nudges at her arm with his hand, suggesting she pull away rather than forcing it.

"I think I can get up now." Maybe. He still feels thoroughly exhausted, but he won't know until he tries.