Energy or lack of after dialysis?

My 80-year old mom has been on dialysis for a year and half. She drives herself back and forth to the clinic about 20 minutes away.

Some days she returns from dialysis and feels fine and ready to go. Other times, she is extremely tired after dialysis.

She wonders why that is happening.

Is she on Peritoneal (PD) dialysis? I felt this way when I was on Hemo dialysis - but never since I switched to PD. Maybe she should talk with her doctor, or the two of you could go together.