I have been a vegetarian for almost two years now - my two year veggieversary is on August 18th! And it was one of the best decisions I have ever made in my entire life. Last year, I tried on two separate occasions to be a vegan. The first time lasted about four and a half months, and the second time was only a month. It was very difficult while at school, as I have to be on the meal plan there, and they are not very vegan-friendly.
Although most of my friends gently tease me about my back-and-forth on this, I really want to try again. Today was my first vegan day, although I often find myself able to go several days at a time as a vegan without even knowing it. I guess, for some people, it seems silly that I keep bouncing back and forth. But it's an issue I just can't let go. Even when I started eating as a lacto-ovo veg again, I still purchased only vegan health/beauty items. So somewhere inside of me, the urge to be vegan never really died.
I want to be a vegan both for the animals and for myself. I know about the injustices of mass farming, and at the same time, I also know that I was never over 140 pounds as a vegan, and when I wasn't eating vegan junk food (mmm, Oreos), I felt pretty good.
I guess I just wanted to share, and wondered if anyone else had similar experiences.

Whenever I felt tempted to eat an animal product, the idea was slammed out of my head by thoughts of animals suffering, the earth suffering, with many items my health suffering... (now why can't I have the same reaction when it's the thought of a delicious slice of vegan chocolate cake and my thighs suffering? yikes, but I digress)
You can do it this time! Good luck!