I don't think going vegan or vegetarian is some magical way of increasing your energy levels. To get those sorts of effects it needs to be done with a decent amount research and planning. I don't think its a good idea to just take the meat out of your diet and replace it with tofu or something else. I think you need to look at your intakes and start to think of each meal in a weekly context - making sure you cover all the important bases each week.
As I explained in detail in a similar thread:
New Vegetarian Feels Tired in Mind and Body
I was vegetarian for 5 years -> carnivore 1 year -> vegetarian 8 months -> now vegan.
The second time I went vegetarian I have felt much healthier, energetic and positive about my diet. I attribute this to the time I've spent researching vegetarian / vegan diets and planning out my weekly meals. I really think it can make a big difference if you are well informed in what can be a big change in your diet.
One last thing:
veganism != deprivation. Veganism has introduced me to more diverse foods (and tastier) than living in China for a year.