Salaamu Alaikum Mufti,
I was woken up by my sister this an hour before Fajr this morning, i ended up dozing off again and in my deep sleep as i was dozing off, i heard in a clear voice someone calling my name, and i replied saying something but cannot remember if i said yes or no. I immediately woke up realising that my door was still closed and that i heard this voice and no one was there. My sister was inside getting done. I just kept quiet not saying what i heard or anything. Is this a concern? Was i just imagining myself or being over tired? I immediately ask Allah for forgiveness (astaghfirullah) and blew 3 times over my left shoulder.