Complex with sex

Hi, im not sure if any one can help me, im a 24 year old male with an ever growing complex over sex. Im in a very happy relationship and I love my partner very much but im unable to make her climax and have an orgasim. About a year ago I was involved in a car crash not a major one but I was off work for eight months I am now back in work but since my crash I dont seem to be able to last for any lenth of time I mean five min and thats it. I dont understand why this is before my crash I was fine and had no worries in that department but now im like a five second wonder. She doesnt even get nto it and I’ve cum, can anyone give me some advuce because this is really starting to get me down I want to give her so much more and I dont no why I cant. Im in tears just writing this im at my witts end. Thanks for reading this and your answers and advice are appreciated crp24 x