What Causes Pain Around Groin And Inabiity To Attain Erection?

I am a 40 yeast old married male. For the last 5 days I have been noticing that I am unable to achieve penile erection (even during times I have extreme desires to make love to my wife). I have NEVER had problems functioning in the past and it is VERY frustrating. I read that impotence could be cause by stress-which I have been feeling if late (I am currently in transition out the Navy, because I am retiring, and trying to find a job). I noticed that when I find myself get aroused, I start feeling pressure around my groin area, but again can not achieve erection. What can I do? Should I be medically evaluated?