Been veggie for 1 year and vegan for 4 years. Made the leap to veggie after watching the Earthlings documentary and went vegan after doing more research about meat/dairy industry. Not here to preach or none of that...just sharing my experience and what drove my decision. Have same amount of energy as before; don't feel any better or any worse. The main difference is I've only been sick once in the last 5 years so that's been a nice benefit. Up until last year, still pretty active (gym, skimboarding, hiking, bball). Rarely do any of that anymore because I got a 9 month old to take care of, and I'm the primary caregiver for my disabled mom- she thinks I'm crazy for being vegan, haha...she's prolly right. I still cook her meals with bacon, beef, fish, turkey, and chicken so I'm not a meat-o-phobe. With that being said, meat no longer really appeals to me although I still find myself enjoying the aroma of bbq or bacon in the air. Side note: I'm 6'2 190 lbs.
Definitely a lot harder for me making the transition from being veggie to vegan than from going omnivore to veggie (giving up In N Out was most challenging) mainly because of eggs and cheese. I've always enjoyed my fair share of pizza, nachos, enchiladas, etc., but most the vegan cheese substitutes I've tried are pretty nasty. Also scrambled eggs taste a lot better than tofu scramble, but I've adjusted over the years. Lots of great tasting healthy meals out there once you start diving into it so I'm not just surviving on "air and tears" as one stand up comic put it haha. Anyway, this was a good resource that I used when I first started up:
https://www.amazon.com/Vegan-Life-Ev...rds=vegan+life
Good luck with whatever path you choose. To each his own.