add and sex

To whom it may concern,

I am a 30 year old white male with add. I am on medication for it and it does help. Here is my problem when I am with my partner and trying to have sex I get hard and stay hard for a while than my mind goes on to other things and I loose my erection and can not no longer focus on sex. I was wondering if there is a way to fix this problem or have any suggetions to help me.

Also it takes a long time for me to ejaculate. I was wondering if that is part of add as well that I am not focusing on it enough.