When does motherhood begin?

I have been pondering this question ever since my miscarriage last year. Yes, I was lucky enough to conceive naturally in Jan 2007, just to have a miscarriage at 9 weeks.

So I ask: what is motherhood? Do you have to have carry to term before you can consider yourself a mother? I don't know. I didn't consider myself a mother when I was actually pregnant. I was in a constant state of shock and nausea. But when the sonogram technician told me she can't find the heartbeat anymore (after I had seen it in a sonogram just the previous week), I experienced a loss the depth of which only a mother can feel. Is that when I became a mother? At the moment of losing my unborn child?