Sexually Transmitted Diseases Community

Approximately 3 weeks ago I began experiencing the following:
-can get an erection but cannot maintain it very long; not long enough to have sex with my woman; I can get erect again quickly after my failure during intercourse and can maintain it and even ejaculate, but only if I masturbate. I am very aroused and stimulated sexually with my partner, so desire or lack of interest is not the problem; I am concerned because this has never happened to me before; I am 57 years old; one indicator might be low iron count in my blood; I went to donate blood just prior to my recent sexual activity about 4 weeks ago and my iron count was 31 so I was not allowed to give blood since the minimum count is 38 for donation. In addition, even during intercourse or with masturbation, I have very little feeling and sensitivity in my genital area which is also unusual for me. Even when fully erect I just don't have much pleasurable sensations like I used to; just kind of feels numb. My doc is out of town for a few weeks so I am looking for some help from someone out there as this is very frustrating to me. I can look at porn on the web, get and keep an erection and masturbate and ejaculate,but still not much feeling in my genital area, even at the poiint of ejaculation.
Would appreciate any thoughts, advice in this matter. I have done research on the web but cannot find anything that clearly addresses my issue; there is lots of information about low testosterone, etc., but the lack of feeling and sensation is not addressed; maybe the low testosterone is my problem and that would cure both issues, the erection part and the feeling part; I just don't know; thanks
Jay