I hear ya!
I got a book called The Highly Sensitive Child - as dd1 gets over cooked easily and I wanted to learn more about this sort of child. I realised the book is about me
Now dd1 is at school and everything has gone up 10 volume levels, and dd2 is a wild woman by nature...I'm finding it all very invasive, noisy and intense.
Noise. Noise is hard to tolerate if you aren't used to it. On days where everything is too noisy and bright for me, I tend to stay out of the house as much as possible. So trips to town, cafes, play gyms, garden centres, any where.
I also think with a 3 yo, it is fine to be firm about your own comfort zone and boundaries. I'd cope badly with the fingers in mouth thing, especally if it caried on after I asked her to stop. I'd feel chlostrophobic [SP?????????] I think it is ok to set a clear message. SImple and clear, in a low tone.
Stop it DD, I do not like it. Stop it now or I will have to stop tucking you in and go downstairs.
Then dd gets a chance, and if she doesn't stop..
DD, I am serious. Look at me and listen. Stop putting your fingers in my mouth.
DD stops, You cheer your voice up, shnuggle her and wish her a lovely sleep.
DD doesn't, wish her a lovely sleep but go.
AM I a strict old bag?