I am 21 years old and I am having a problem with losing my erection during sex with my girlfriend. I am very concerned since I am only 21 and I know that losing your erection at that age is not common. It occurs every once in a while, and sometimes in streaks when I seem to lose my confidence and it is quite a blow for me psychologically. It is seeming to happen more and more, even though my stress level has gone down. It does not always happen, but it seems that sometimes I just really tighten up and can’t seem to relax; it’s almost like a stress response in my body takes over and I shut down, even though I don’t want to. My girlfriend is obviously frustrated about this, but has been wonderful about being understanding. I have trouble relaxing and just sitting back and enjoying the experience, since I get concerned about losing my erection or wondering when it might happen. I am incredibly attracted to my girlfriend and am very frustrated that I cannot seem to solve the problem by just making it go away. Running through my mind are always thoughts of “what if it happens next time” and “why can’t it just work like normal?” My stomach tightens up and I kick into an anxiety response kind of thing, where it makes my blood pressure go up, I bet, and just gets me a little nervous. I don’t have a problem when it is just me (with myself), but I seem to tighten up when it is the two of us. So please, doc, any help you can give? Are there ways for me to keep myself from tightening up and losing my erection? Or am I just suffering from something else, like a lack of testosterone that fuels my sex drive?