Hair loss can be related to lack of iron or thyroid problems.
If you are eating enough greens for iron, then your next step is to to ensure you are including legumes in your diet... beans, lentils, peanuts.
According to veghealth
: "The amino acid L-lysine plays a part in the absorption of iron and zinc. Among plant foods, L-lysine is only found in high amounts in legumes, and a vegan who doesn't eat many legumes could find themselves falling short on lysine. "
To prevent thyroid issue, make sure you are getting enough iodine. (found in iodized salt or sea veggies). You need about 1/4 tsp iodized salt per day. If you don't use iodized salt then you should be eating sea vegetables or taking a supplement.Veghealth gives a breakdown of exactly what you as a vegan should ensure is in your diet.
I agree.. it is not as easy as being omni... but if you follow those recommendations from veghealth, you should be covered. Good luck.