I am 24 years old and have erection problems. I've only had sex 3 times and each time was tough but it was okay when i was on the bottom. I have never been able to achieve an erection while standing and this goes for both masterbation and for sexual intercourse. I can only achieve an erection while sitting or lying down on my back... If I stand up from these positions even in the height of sexual pleasure I almost immediately begin to lose my erection, even while im almost about to have an orgasm. I have achieved an orgasm while standing two times in total. Each of which was down with a 1/3 flacid penis that was no where close to being able to achieve intercourse. I don't know if the problem is physical or mental but I don't know what to do. I wake up with morning erections. I desperately need help and no one on the internet I can find has a same problem so it's plaguing me. Thankyou