You gain more energy!
One thing that happens when you go vegan that people are surprised to observe is that they end up gaining way more energy than they had before. Many people believe that in order to be able to perform well at the gym, you need meat-derived proteins, but in reality, you just need protein, and you can get it from a plant-based diet. It has become a bit of an overused cliche to hear new vegans list among the things that happen when you go vegan that they have way more energy, but it is indeed true, and we cannot lie about it!
This is not because eating a vegan diet is going to suddenly make you feel invincible and fill you up with a lot of energy, but rather that if you are going from a less vegetable-filled diet all the way to a nutrient-filled one from a plant-based diet, you will observe the change immediately. It is also a reaction a lot of people who have taken out excess meat from their diet have observed, so sometimes too much animal protein can be detrimental to our health, especially after a big meal.
Nothing is guaranteed, but if you always feel tired, adding more plant-based dishes to your diet may be the key!