I can't help you with knowing whether or not it's an amnio leak but I was quite often wet down there and got quite irritated too because of liners, it even got to the point where undies did it too and I had to change quite a few times most days. So it seems like it is normal (someone correct me if I'm wrong) the only time when it can become and issue is if it's coloured or it smells bad and funky, this could mean that you have an infection and you should seek medical advice. But otherwise I'm pretty sure what you've described is normal.

Hopefully someone can answer your amnio question