It's likely due to a tolerance you have created by regularly consuming caffeine. If caffeine seems to have little effect, that is quite worrying because it implies that you have a huge intake to have such a huge tolerance. It's not good for you to have caffeine running through your system all the time, even if you are able to sleep ok. It's not a super power unfortunately, it's a health risk.

Edit: When I had a drinking problem, I could drink a bottle of wine and not feel drunk because of my tolerance. At the time I just thought I had a superpower of being able to handle alcohol really well. Nope. When I quit drinking and then occasionally had one drink, it would floor me because I had lost my tolerance. Alcohol and caffeine are drugs, which is why I think my experience relates to yours.