Have to leave baby in NICU today 😞

My baby was born at 36+5 weeks he's perfect but very small in stature due to complications with IUGR. He weighed 3lbs 15oz at birth (Oct 19) he's doing very well.... he's never had complications with breathing, eating from a bottle, as you can imagine he's just like a 37 weeker but very small. I'm getting discharged today and feel so heart broken that I have to leave him behind at the hospital. How did you cope with leaving your baby during their stay in the NICU ? I feel like I'm neglecting him. He probably won't stay for too long but it hurts me alot