Struggling to keep erection need help!!!!!

I'm 23 years old and just recently have started seeing a girl (sexually) now there was no problems the first time we done it but nor a few after but lately I have been struggling to keep an errection and to be honest it's down right embarrassing. I have no problems when I masturbate ( which I feel had gotten out of hand lately) so was looking at forums about ed which sent me here. I was just wondering if anyone else has had the same issue and weather this forum had helped. I don't even know if anyone will read this but hey ho it's worth a shot.