@Lonelyboy17 like @WheresMySquishy said, it's hard to know without context. That said, a few possible meanings:
They don't want a relationship right now,
They don't have a crush on anyone currently
People are annoying them/ they're introverted and not getting the space they need
They're asexual/ aromantic and just aren't "into people" in those ways
Or something else entirely..
Your best bet is probably going to be asking them to clarify what they said though; we can only really guess at what they meant over the internet, which makes it a lot less reliable...