Is the ticking in my head? Is the clock about to expire?

How do you know that time is almost up if you're just moving along in life at your own pace and you never stop to look at the clock?

Somedays, I hear it in the distance. The tick-tock of the time that I have left here. 

While I was living, somehow almost 54 years have gone past, and, now, I am starting to hear the tick-tock more often.

It becomes louder as the days pass. Yet, you just keep living for the next minute, the next hour, day, week, etc...

I may not have long on this earth, but I will keep working until the final...

tick-tock.