Advice about toddler bedtime?

Ok since 4 weeks old she slept 11pm till 7am and from 11 weeks onwards she has slept from 7pm to 7am no problems at all. She is 2 now. Recently she has been taking her nappy off in her cot when she wakes up. Usually she is dead quiet and doesn't call for anyone for at least 10 mins so i dont know she's up. So every day twice a day on most im washing her bedclothes because she has done the lot. Wee and poo everywhere. We started potty training and even put a swimming costume on over her nappy and under her pj's. This worked for all of three days :(. So ive decided to turn her cotbed into the bed so when shes awake she will rather come and find us than taking her nappy off. It has worked except it takes her ages to fall asleep. ie. running around on the landing. Ive tried repeatedly putting her back and saying nothing and also sitting in the room till she falls asleep. Im nearly 20 weeks pregnant and am getting quite tired and i need some help/advice on how to get her settled. Once she is asleep she does sleep through the whole night. Its just the first part that's the problem. Thanks in advance.