How can I feel connected to Sai Baba when he is no longer in his physical body? I feel like my devotion is stagnating.

Chapter 43 addresses this very concern by explaining that although Baba left his physical body, his presence is eternal and unbroken. It is stated that he merged himself into the unmanifest and continues to stay in the hearts of his devotees. For the sake of his devotees' salvation, he would engage in the spontaneous play of Yoga, and his departure was a similar act. He consciously burned his body in the fire of Yoga and attained his previous unmanifest state. By merely remembering his name, the worries of birth and death vanish. Even in his unmanifest form, he enjoys his true self and always keeps his devotees awake, proving that his connection with them is perpetual.