I don’t know the cause of your erectile difficulties, but I think it IS possible you could have injured yourself. I think you need to find a Urologist whose specialty is treating cases of ED, and such a Uro would likely be in favor of doing a Doppler ultrasound to measure inflow & outflow of blood.
As you seem to know, even if inflow is adequate, blood needs to remain trapped in the penis for an erection to occur, and weak (or total lack of) erections is often related to venous leak, which is a failure of the mechanism to ‘trap’ the blood, therefore, it leaks out & a full erection can’t be obtained or maintained. It’s like trying to fill up a bucket with a hole in the bottom.
Try to get a referral to a Dr. who specializes in treatment of ED - I think that’s your best bet. Good luck to you & let us know how you’re progressing...