i went omni to vegan instantly. a friend loaned me a PETA magazine and i read it and was horrified by some of their articles on factory farming. i then sat down to my favourite meal of chinese food, all with meat, and didn't enjoy a crumb of it. later i went online, did a little research, found this site and realized there are a lot more vegans in the world than i thought, and just sorta said to myself "ok i'm vegan now"
and i stuck with it, maybe not 100% and i had a few minor slips (mostly involving milk chocolate
) but i'm pretty proud of how i stuck with it especially after my family and friends said it was a phase and i'd be back to eating meat in a week.
anyway the best advice i can give is if you plan to go straight from omni to vegan, give it a couple days and ease yourself off the meat and dairy. set a specific goal like you'll be vegan by this time next week and take that time to try some vegan dishes but don't limit yourself completely from meat and dairy yet.
when i switched i did it too quickly and though i don't regret it, it was hard on my body. i had some wicked stomach aches and digestive.. uh.. issues.. for a few weeks. just my body working out all the guck from years of eating crap. but it was unpleasant. so give yourself a few days and don't beat yourself up over slipups, we all have them, especially when we're first making the change, it's no big deal and yes you're still vegan if you accidentally (or purposely) eat a small amount of something unvegan once or twice. being anal about it will only make it harder and make you less likely to keep at it.