I am faced with three signs
One is shared between us
One is very small
One is sold again
What can I tell from these, and what does that make me?
What can I tell from these, and what does that make me?
You tell the time and that makes you a watch or clock.
I am faced with three signs
Your face has three indicators for hours, minutes and seconds
One is shared between us
Hour sounds like our
One is very small
Minute
One is sold again
Second hand
The title: My Days are Numbered
The day and date number
This is an awkward (and 99% wrong) solution, but I thought it might be funny. I think you are:
The Past, the Present, And the Future
The Present is between the other two
The Past is considered to be small
And... you can re-sell presents?
All that and the problem is named "My Days are Numbered"
Something tells me you meant that literally...
Yeah this answer makes no sense but it was an idea :D
Partial answer
Since there is the wordplay tag, I think "One is shared between us" is
T (t). T is between us (U and S) in alphabets.