If this is Two... Can I Skip Straight to Three?

My precious daughter is not quite two. But she's rapidly descending, and it will not be long before she celebrates with us her second year of life. I love my daughter more than there are stars in the sky... but lately, I've had moments where I havn't... well... liked her all that much.
Angel child becomes...

There, I've said it.

I've never felt this way before now, and it gives me the guilts. Big time. But I can't help it! My daughter has - almost overnight - developed certain personality traits that grate on me like fingernails on a chalkboard. Screaming when she doesn't get her way, for instance. Shouting "NO! MINE!!" when children come over to play and dare to touch one of her toys, for another. My daughter, when she wants something, has no patience waiting for it. We have about 2 milli-seconds to get the said thing she wants before she goes into full meltdown. My daughter has developed a frightening addiction to her dummy and the idea of extricating it from her fills me with horror and dread. She demands 'bitties' (biscuits) when she knows she can't have one. She thinks it is funny to stand on my bare feet with her shoes on. When my back is turned in the supermarket I turn around to find her standing precariously on the seat part of the trolley. Just to spite me.

Other days, my daughter is a beautiful perfect angel and I pat myself on the back for having such a delightful child.

Lately those days are few and far between.

In my heart, I know it's not something I've done. Not consciously. But has my over-indulgent-first-time-parenting created a not quite two year old monster? It all came on so suddenly that I have no idea how to cope or what to do about it.

... she monster. Or maybe just a bad hair day?
A friend kindly suggested recently that this behaviour can be a sign of great intelligence! But at this rate, I'll be enrolling her in baby-Mensa! It's true (jokes aside) that my daughter's language is exploding at a rapid rate of knots; her level of understanding and comprehension is very impressive and she seems to be able to count to ten. And, let's face it... she's smart enough to have wrapped her degree-and-life-qualified mother into a tailspin??!

I havn't got any 'toddler manuals' - perhaps you could recommend one to me? Or give me advice on how to cope with this little person on the cusp of terrible-2? Or assure me it will all go away as suddenly as it descended? Dear friends, I want my angel back!