Why haven't i had an erection in 2 days and why does my penis feel empty and small and cold ?

Get evaluated.: If you have a sudden change in the appearance and function of the penis, get seen by a physician who can evaluate it quickly. It's not possible to make a diagnosis now, but a thorough history, physical exam, and possibly some tests such as a penile doppler ultrasound may be necessary to find the cause and guide treatment, if necessary.