After many ups and downs I realized that just quitting caffeine wouldn't make me feel that great amount of energy I was looking for. It took me a while and some trial and error to discover what works for me, and given that every body is different ymmv. But for sharing purposes here's what fixed my never ending low energy cycle (besides quitting caffeine):

· Boosting my testosterone levels - most people don't realize that the majority of men nowadays has low testosterone issues, and low T affects a person in many more ways than we are used to think about: lower libido (obvious), feeling tired all the time, depression, even hair loss (yes, low T too can make you go bald), no drive towards any activity etc. A simple blood test can confirm that. To get me to more decent levels of testosterone I begun exercising more, keeping a workout schedule, and I supplement zinc, magnesium and vitamin D. To exercise targeting to increase testosterone != simply exercising, so do your research and preferably consult a professional;

· Trying to keep a fixed and decent sleep schedule;

· Dietary aspects: 5 day fasting (research before doing anything like this), followed by a zero FODMAP diet for over 10 days with the addition of some probiotics. After that I adopted a intermittent fasting schedule (a window of 6 hours / day to eat, so 18h of fasting every day) and avoid to consume nightshades as much as possible. The idea here, although there's a lot of debate in the medical field, was to first clean and repopulate my intestines with better bacterial colonies, and to prevent what people call the "leaky gut syndrome" afterwards. I'm also trying to avoid ANY kind of processed oil, even olive oil, and my sugar consumption is quite minimal (no sugar at home ever, no processed foods (so no hidden sugar), rarely eating anything with sugar when I go out).

Some of these measures may sound extreme, but that was the only way I managed to fix my energy levels. I'd say 80% of the issue was due to low testosterone, I really advise you to test your blood for that. The other aspects also helped a lot, not only with energy levels.