The relation between Modafinil and anxiety is complex. Modafinil can improve or worsen the symptoms of anxiety. From studies, it is concluded that genetical factors, current mental condition, and drug interactions can increase the possibility of experiencing anxiety from Modafinil. 
Read this blog to understand Modafinil and its effect on anxiety. 
https://www.onlinepillswww.com/blog/modafinil-anxiety/