bottle weaning

My LO is 14 months and she uses a sippy cup at daytime and she takes a bottle before bedtime and nap time and she won't drink milk from sippy cup. But her sucking yo bottle is getting worse even when the milk finishes she won't leave the bottle and would want to suck on it. I want to wean her but in afraid she won't get enough milk from sippy cup and also what did you parents do when your LO wakes up at night after or when you were weaning from bottles. Any help is appreciated!! TIA