unable to wake even when there are loud sounds

I am having this problem for past 1year sporadically.  But today's was a major issue.

I was feeling very tired and went to take some sleep when my husband went to collect my daughter from school which is pretty near (10 mins). He didn't carry the door keys. Once he was back he tried door bell several times, when it didn't work he tried calling the residence phone and then even my mobile. My mobile was just beside me but I couldn't hear it. It was around 20 mins, he panicked and start banging the door, ultimately broke the lock to enter. And all the while I didn't hear a thing, in spite of all these huge noises. After they got inside, I awoke at the sound of my husband talking to me in high pitch.

I am really worried that all these different noises could wake me. What may be the reason for this?
Just to mention I don't have any hearing problem.

[Gregg D Jacobs, Ph.D.]

You may have an underlying sleep disorder such as sleep drunkenness, which is characterized by extreme difficulty being awakened. You should ask your doctor for a referral to a sleep clinic for an evaluation.

Dr. Jacobs