I guess if I were you I'd be thinking about how I could sustain myself better whilst being a vegan. It is possible, just as long as you eat the quantity of the carbs, protein and fat you need, regardless of where you get it from.

A dietician might be able to help you with that if you cannot figure it out. Of course it'd be hard work to make sure you're getting everything you need, but it's not impossible if you are open to eating a variety of foods.