Well, at least one mystery is solved.
When you picked up the film after it dropped, you picked up the other end, and therefore loaded it with the last photos going first into the centre of the developing reel.
If it is any consolation, I've been doing this for 40+ years, and I too sometimes have trouble with a film that refuses to load easily. So it may be that you are being unfair to yourself when you describe this as a "very rookie mistake". The big advantage of course of having more experience is that it is easier to stay calm under the pressure .
Humidity (either very low, or very high) is often the culprit. What type of reels and tanks are you using?