Kho Gaye hum kahan

I'm not sure if this is the correct place to ask this but I just heard this song from Baar Baar Dekho and I'm in love with it, it's so soothing and melodious to hear ❤️  But unfortunately I don't completely understand the meaning of the song, so can someone help me please? 😳 I don't want a direct translation of the lyrics, but the meaning behind it. I mean is it two lovers dreaming of their future together, or thinking of some 'alternate' world where they'll be together or what?