Bluetooth is not finding keyboard or mouse

If I close my Macbook for several hours, when I open it up again I receive an error message from Bluetooth Setup Assistant stating that there isn't a keyboard connected. I have no functioning keyboard or mouse - bluetooth or the actual laptop trackpad or keyboard. I have to result to a hard reboot every time. Any ideas as to what the conflict may be? I'm running El Capitan (10.11.3)

Thank you!!