Sophia went through a similar stage when she was very young, she would only sleep if I held her or if she was lying next to me in bed. For a couple of months I simply sat comfortably reading a book or watching TV, or had a nap myself, or carried her in a sling. Then one day something made me try to put her down after she'd fallen asleep and she stayed! Over the next couple of weeks I slowly got her used to having all her sleeps alone. THat was a long time ago and she now has all her daytime sleeps on her own.

I think sometimes you just have to forget all the "rules" and advice and do what you have to do.