Due something about Anivia's mana cost.

Ok so first off here's the thing with and I'm at about 3.7 mana regen I think. With the old runes and masteries I was getting 7 mana regen.

Another thing about her is her abilities are so mana expensive.

Q:80-120 mana W:70 E:50-90

And her starting mana is 396. That's like what two or three shots and she's useless?