Hello Jamie Thank you for posting your quarry here. You are having performance anxiety that makes difficult erection when doing sex with girlfriend. And same anxiety reduce excitement and level of arousal during sex causing delay or absent orgasm/ejaculation. You can try sex in comfortable environment and after taking your partner in confidence. It will help to reduce anxiety. Other anxiety relieving measures like breathing techniques and yoga may be helpful. Anti anxiety medications can help to alleviate anxiety symptoms- can be available from prescription of qualified psychiatrist. Hope this answer your quarry.