Bloodborne disease!!!!!!!
I honestly think it's stress, but I could be wrong.
According to the scientific research and results on this topic, Vicky would not be able to satisfy the demand of her body for protein without consuming any products that are derived from animals.
Vicky's goal and intentions are good and noble ones, as she loves animals, respects them, and do not want them to be slaughtered so that she can eat them. Unfortunately, her body would not react good to her stopping consuming all animal products, especially if she has a blood type O.
The humans are omnivores, thus consume both plants and animals and the products of the animals. The human body needs meat in order to get enough iron, so the chances are very high that Vicky will become anemic very quickly, especially by being a volleyball player and spending much more than the ordinary person. Also, the human body process the proteins from animal origin the easiest, while it finds it hard to do the same with the proteins from pant origin, thus Vicky will soon become much less energetic and not be bale to perform as good as she did earlier. The brain functioning will also be affected, as it is the organ that needs the most energy and by lacking it, Vicky will start to have troubles with her concentration and thinking process.
