I'd recommend 'The Shadow of Anxiety'. The protagonist in this light novel has severe anxiety and the plot follows their struggle to find peace and acceptance. The story is full of emotional depth and realistic portrayals of anxiety.
One such light novel could be 'The Fragile Mind's Journey'. In this story, the main character constantly battles anxiety while navigating a complex world.
You might want to check out 'Anxious Hearts'. The main character here faces anxiety and tries to overcome it while dealing with various challenges. The author does a great job depicting the inner turmoil and growth of the character.