Support.

It is usually the hardest thing in the world to stand alone on a topic that you feel strongly about.
The thing that you really need to sustain the strong foundation is support. All you need is that group of people that you can lean on and cheer you on as you reach your goals.
I, personally, as a vegan, have often undergone an illusion of support from my friends and family. Often they say "Oh, I could never do that, good for you" and then next thing that you hear from them when you ask for support is "you made this lifestyle change, not us." And there you are left, with the foundation cracking under your feet.
But you just have to stand strong, and hold your ground, don't let your efforts falter.
Stay Strong. I Support You.