No no, from what I read, the whole “When i was a child, i had a fever”, related to exactly that. When he was a child, he had a fever. That is how he felt. Definitely though, I can remember having fevers as a child that made me mildly hallucinatory. I don’t think drugs are necesarily involved here except the drugs they are implying that Pink is being injected with. I also imagine that might be relating to an experience as rock stars. The whole thing about The Wall is that it reaks of experience. Unlike the following “David Gillmore Pink Floyd”, the whole thing is filled with genuine heart and not pretentious at all.
ETA: While Roger Waters work post Pink Floyd may not be as great as the Pink Floyd era, it is still very genuine. It’s very much what is in his heart. That is why I think Rodger Waters is the heart of Pink Floyd. As great as the music got, Rodger Waters never pretended it was anything other than himself.