I was a very healthy sexual male until about a month ago, and began experiencing impotence and now just can't stay hard for long. My stool has changed more reddish, and not as solid, i got an std test, and some more blood work done, nothing was found yet. I'm tripping because i just met a new girl and she wants to have sex and i'm unable to, cialis didn't really work, i still lost my erection. What is going on with me. I'm not using drugs or alchol excessively, i get a good amount of exercise. My penis and testacles feel kind of cold. I'm not depressed or anxious. i had been taken a lot of supplements but cut these out to see if this was the problem, still nothing has changed and not even drugs like cialis help. I'm worried could i have cancer, or an std, any insight would be so helpful,