That Sherlock wasn't protesting at all, about anything and just agreed with whatever Greg was offering and telling him to do, was probably the most worrying of it all. He sat there for a little longer, watching the other man, whose eyes were closed. He was clearly not sleeping yet and Greg was hesitant to leave him alone in this state, even for a second. He gently patted the other mans blanket covered knee. "I will be right back." he told him softly and got up.
"Are you hurting? I think the pain meds they gave you at the hopsital must have worn off. Should I get you some?" he asked, knwing though, that for them to work, Sherlock would have to be fine enough to not throw them up again though.
As Greg headed out of the room, he quickly knotted the bag from the bin and disposed of it, getting a new one, before he would head down to Mrs. Hudson again. No need for Sherlock to have anything around to make him feel even sicker than he already did. And after everything Greg had already seen in his carreer, this didn't even faze him. 
Hurriedly, he headed down, to Mrs.Hudson, this time not explaining much, just asking her for some herbal tea that might help with settling an upset stomach and went right back up, pouring the tea himself and carrying t back to Sherlocks room, where he set it on the bedside table.
"So, pain meds?" he asked again, not having gotten any yet, because he wanted to wait for an answer from Sherlock. If the man didn't trust himself to keep them down, it wouldn't do much good, after all.