Still waking up in the middle of the night

My 11 month old is still waking up in the middle of the night. He refuses to go back to sleep until we take him out of his crib and feed him and put him back to bed. We have tried the crying it out method and he never stops crying. My husband has let him cry it out for more than an hour and he still won't go back to sleep. He gets up sometimes 2-3 times in the night always between 1-5 am. I have tried giving him water and he will drink the whole bottle and then want more, he won't drink it though unless you take him out of the crib. We used to be able to just give him a bottle and he would lay down and drink it and go back to sleep on his own and now for the last 3 months he refuses and throws the bottle. I just don't get it, he goes down fine at bedtime barely cries and has no trouble falling asleep. Separation anxiety?