overestimated vs. overawed vs. overwhelming vs. overloaded

[Annaa]

Hi,

I have the following sentence to fill in.

1. Despite the ..........(overestimated,overawed, overwhelming, overloaded) sensation of living with eight million people, students......... (stem, wave, pounce, flock) to the city's universities.

What would you choose?
Can you explain me differences between these words?

Many thanks
Anna

[Annaa]

well I have another question. What collocation is appriopriate?
...........of pay
a)rates
b) terms
c) conditions
I think about answer c, but I am not sure about the rest.

Thanks for your help.

[Pamela]