I've racked my brains for the moment I went soft. It should be stamped on my memory in indelible brain-ink, because I'm pretty sure than until that point I was the fiercest, meanest, most acerbic bad ass in the dog-eat-dog world of arts journalism. Well, I once made John Peel cry, and legendary American novelist Richard Ford almost slammed the phone down on me. That's rock'n'roll in the arts world, trust me.

Forward a few years and I've morphed into a woman routinely mocked by her family for an inability to hold back tears at the slightest suggestion that someone somewhere is peeved by something. And Christmas is the most perilous time of all. I try to guard against it. I told myself in no uncertain terms during the John Lewis advert in which the excited wee boy wakes up early to get his gift to his parents that it was a cold exercise in Stalinist mind-control (some weird kind of commercialised, deeply Capitalist Stalin). But I cried anyway. Buckets. And briefly investigated the possibility of adopting the little boy.

I cried when Rev's wife told him she was pregnant on BBC2 on Tuesday night. I cried when I saw a pin-striped man having the breath squeezed out of him by his excited old mum at the airport on Wednesday. And my God did I make a fool of myself at my five year old son's Nativity. I think it was the lop-sided deely-boppers that did it, or the tiny black leather shoes sticking out from under his white star-clad sheet.

I've always been a bit delicate when it comes to films, books and TV shows. I wasn't the dripping tap I am now, but a well-written heart-tugger could always disarm me. I locked myself in the bathroom for half an hour after finishing John Updike's Your Lover Just Called. When I saw Edward Scissorhands at the cinema I had to be virtually stretchered out by my humiliated boyfriend, so incapacitated was I by grief (come on - despite an infinite capacity for love Edward must be alone forever, but the people in the town always know when he's creating another magnificent sculpture because as he chips at the ice, snow begins to fall on the valley; check yourself for a pulse ).

But at least in those cases I was having an intellectually justifiable reaction to a high quality work of skill, an art lover's empathetic response to an auteur's attempt to provoke feeling and thought. Courtney Love probably cried at Edward Scissorhands. It showed emotional intelligence. Can I really make the same argument for swallowing a throat lump when Spongebob Squarepants' gets a new pencil case?

Of course there's a good chance it's having children that's made me so much more vulnerable. Maybe the fear of a loss that could break you in two in a heartbeat makes you permanently emotionally shaky. Or perhaps it's simply getting older, facing the horrible truth that nothing lasts forever, that the time you once saw rolling out in front of you for an unimaginable eternity now bashes at your consciousness like a constantly nagging egg-timer. Once you were Peter Pan. Now you're the ticking clock-haunted Captain Hook.

Maybe I'll never get my edge back. But if you see me this Christmas, red-eyed in front of a bunch of warbling carol singers, nip me in the arm and tell me to wise up. Without your help, I'll be Daniel O'Donnell by Easter.