So you somehow injured yourself doing pe and it might have been made worse when that girl landed on you badly? Is that what you're saying?
I'm not a urologist or doctor but I understand that there are several possible causes of erectile disfunction. What you describe could also be peyronies disease. But first you need a good diagnosis and it seems that you need to find a doctor you trust.
You also talk a lot of your insecurities, but I'm not sure if you're referring to long standing insecurities or about insecurities that stem from your possible injury. If your cock is that size you say it is then you certainly shouldn't have insecurities about cock size. Either way, I hope you get to the bottom of this as you are obviously worrying and that isn't good for you.