Young lonely nerdy guy thinks he’s and alien left on Earth by his father to eluded evil aliens. He meets a cute girl and falls in love. In the story plot you are led to believe he’s delusional. His psychologist convinces his girlfriend and then him that that he’s crazy. It turns out he’s actually an alien and his psychologist and her goons are the bad aliens. He uses what was thought to be a toy ray gun to defeat them. I can’t remember who it was, but the psychologist is a well known female actress.
I believe this was made in the British Isles 4-5 years ago and was an obscure cable movie. Only saw it once, but would like to find it again. This movie had a great hard twist of an ending, he really was an alien!