Feeling lonely is not the same as being physically alone. It is the feeling that you are not emotionally met, even when people are around. That is why loneliness can show up in a crowd, at home, or in a room that should feel familiar but does not.
Modern life can make the feeling harder to name. There is more contact, but not always more connection. Fast replies can still feel empty. Busy days can still leave you unseen. This page explains loneliness clearly so the reader can understand the feeling before they try to solve it.
Start by naming the feeling instead of fighting it. Then move toward one safe conversation. If loneliness has a sharper shape, read I have no one to talk to.