Hi there,
Firstly can I just let you know you are not alone, I too am having problems with my toddler, Charlotte who's nearly 2. I have an older child who now sleeps ok. Charl is not only completely out her routine but is also being a nightmare child in the day as well. Everyone just says oh it's the terrible two's, but that doesn't help when she wakes at two in the morning screaming and then doesn't settle again til 4.
Like you I have tried what I think is everything but if things don't improve for me then I may call upon my h.v. for some assistance, is that something you have done yet?
I'm sorry I cannot offer positive advice, but it's 'nice' to know you are not the only one.
Take care, Zoe xx