Feeling overlooked by those around you is often the result of a combination of factors. Some of these might include the way you interact with others, or the things about yourself that make it difficult to express your emotions. Depending on the reason for feeling invisible, you may find it helpful to seek a therapist who can offer compassionate guidance and support.
For instance, if you struggle to show your emotions or speak up in conversations, people might ignore you or forget about your contributions. In turn, this can leave you with a deep sense of loneliness and isolation. Feelings of invisibility can also arise from a history of emotional neglect or abuse, leading to a fear of getting close to others. This can create a vicious circle in which you keep yourself at arm's length, resulting in others ignoring or overlooking you.
Invisible people are a popular motif in fiction, from H.G. Wells’s The Invisible Man to The Chronicles of Narnia's Figment. Although a Harry Potter-esque invisibility cloak is yet to be invented, scientists have made some progress with a technology called transformation optics that works by changing the path of light. This can render a transparent object (like a ruler or hand) invisible, but it’s not perfect. If you move the object, or even blink, the effect is broken. Moreover, the invisibility only applies to visible light and not infrared or ultraviolet.
For more on the subject, read our article on How to See an Invisible Person.