A semi-colon always marks a ‘compound’ sentence, for both what precedes and what follows a semi-colon must inclused independent clauses. The semi-colon marks a new idea:
I heard her sweeping away; and soon after she was gone, I suppose I had a species of fit…
Jane hears Mrs. Reed sweeping, and then has a fit. A semi-colon can always be replaced with a period; its use marks the two clauses it separates as a bit more closely related than separate sentences would be.
But a colon does not necessarily, or even usually, mark a ‘complex’ sentence, for what follows the colon may be an independent clause, a dependent clause (rarely), or merely a phrase or word or list. A colon marks what follows it as an enlargement or explanation or more detailed definition of what comes immediately before it:
… I suppose I had a species of fit: unconsciousness closed the scene.
The “unconsciousness” defines the “fit” and provides evidence for Jane’s supposition.
The entire sentence is in fact ‘complex’, but this is because “soon after she was gone” is an adverbial dependent clause. The ‘complexity’ has nothing to do with the colon, which in this case is followed by an independent clause.