EXCLUSIVE

Howard Stern Wack Packer "Crackhead Bob" was hospitalized 2 days before his father found him dead ... TMZ has learned.

Bob -- real name George Harvey -- had been "feeling weak" according to his father ... who told cops his son had long suffered with high blood pressure and seizures. He also said Bob had previous strokes and a heart attack ... all symptoms consistent with someone recovering from crack abuse.

He was admitted to a hospital on January 18, and was supposed to have a follow-up doctor's visit on January 20. His father told cops ... when Bob didn't show up at the doc's office, that's when he went to his apartment.