Krsna has two kinds of presence-prakata and aprakata, manifest and unmanifest. Both are identical to the sincere devotee. Even if Krsna is not physically present, the devotee's absorption in the affairs of Krsna makes Him present. This is confirmed in the Brahma-samhita (5.38):

Due to his intense love, the pure devotee always sees Lord Krsna present within his heart. All glories to Govinda, the primeval Personality of Godhead! When Krsna is not manifest before the inhabitants of Vrndavana, they are always absorbed in thoughts of Him. Therefore even though Krsna was living at that time at Dvaraka, He was simultaneously present before all the inhabitants of Vrndavana. This was His aprakata presence. Devotees who are always absorbed in thoughts of Krsna will soon see Krsna face to face without a doubt. Devotees who are always engaged in Krsna consciousness and are fully absorbed in thoughts of Krsna certainly return home, back to Godhead. They then see Krsna directly, face to face, take prasada with Him and enjoy His company. This is confirmed in Bhagavad-gita: tyaktva deham punar janma naiti mam eti so 'rjuna (Bg. 4.9).