I am a 25 year old male, and have never had any trouble whatsoever with achieving an erection. During the last 5 days I have been unable to achieve an erection at all, no matter what I try, or even naturally when sleeping. I am not currently sexually active. I don't know if there is any correllation but this week I also had a fever of about 103 and the flu. I am wondering if this could be some sort of side effect? Is this a commont problem for someone my age? Is it temporary? Is there anything I can do? How long should I wait to see a doctor?