sleeping help 6 months

Lindsay
My daughter has good naps during the day, has 3 meals, 600mls of milk but at night she wakes every 2 hours and either wants more milk or just a hug. 
I read somewhere that 600mls of milk a day is what is needed when weening and to just give water during the night. Tried this and she was awake every 20 mins. 
We have a routine at night: dinner, play, bath, milk, bed and she goes down fine and you think you've cracked it and she'll be asleep for hours and then she's awake before you know it. 
The lack of sleep is starting to take its toll and I'm getting really run down. Does anyone have any advice?