I was just wondering why my reputation hasn't changed after I deleted two downvoted answers and one downvoted question.
From what I can see of your reputation, you do appear to have recovered the losses incurred from downvoting.
Your "exact origin of the English language" question resulted in a net movement of reputation of zero on November 25.
We don't normally post screenshots of what moderators see, so I don't particularly want to do that. But I can't see any error in the way the system has handled the reputation calculations here. It is a stable, robust and tested mechanism.
This is the time, though, to restate a warning about deleting badly-received posts. They still count in the automatic quality check. Rather than removing posts, you should attempt to improve them. With off-topic questions, it can be difficult to make them on-topic, so you need to be sure to post on-topic questions in the first place (but you removed your question without the community deciding it was off-topic). There is a question on MSE, the network-wide meta.stackexchange, about the post bans which can result from too many low-quality posts: deleting them only makes it more difficult to recover the situation because they remain low-quality.
I can't tell whether you're in any danger of triggering the post ban: I don't know what its criteria are; it's automatic and it just happens. You may be OK at the moment. But if you try and model your questions and answers on upvoted posts by high-rep users, you may receive more upvotes and find that you feel fewer deletions are necessary.