I was Vegan for 8 months and didn't supplement B12. I'm not vegan anymore was that time long enough to do damage or have bad deficiency?

How do you feel? I am very glad you wised up. As a moral choice, you can be a vegan and if you supplement wisely, you will not be risking your health. The health benefits of vegan ism are elusive if they exist at all. If you can walk and think and remember and your extremities feel normally, you escaped the bad stuff.