My tank took 6 weeks total. I thought it was cycled as my ammonia was 0 etc when I tested it but it wasn't quite done.
It's difficult to understand why and how the cycle can hurt the fish when you first get into saltwater fish. On your first tank I think a lot of us were excited and somewhat impatient. That's normal. The disappointment of losing a fish and not understanding why is discouraging. I've known people who went and bought a bunch of cool fish after their tank cycled just to have them die because they either added to many to fast and their biological system didn't have time to adjust which causes issues, or they didn't quarantine them and they ended up dying. Here is a link that may help you understand the cycling process a little better:
In my opinion, I would order some live rock to cycle with. It's good for the tank and it will be your primary source of good bacteria.