I think doubt about the nutritional value of veganism is at the same stage as vegetarianism was about 30 years ago. I remember when I was little, everyone was terrified of having a vegetarian child. These days, vegetarianism has been accepted as healthy, and I presume in a few decades time, the stigma around veganism and nutrition will go the same way. I remember going into the doctors with a sore ear and being offered a blood test on the side just because I was vegetarian!
As a person raised on entirely vegetarian food from birth until 15, and then vegan from thereafter, I've never had a problem with getting any vitamins I need. I grew to 5ft 8, have never been underweight, and have larger biceps than my husband, so certainly not weak and wasting away.
What do you eat in an average day? Maybe if we got an idea of what your general food/diet was, we could suggest additions to it?