'Misgiving', often used in the plural, means concerns. If you have misgivings about something, you are doubtful or worried about them, and you think they will have bad consequences in the future. The Cambridge dictionary has this example: 'Many teachers expressed serious misgivings about the new tests.'
'Disquiet' is more of a general feeling in a place or among a group of people - it's an atmosphere of unease. It's also quiet a rare word. I've never used it.
'There's no + gerund' is a fairly colloquial way of saying 'it's impossible to'.
Here's another example: 'Are you sure you want to do this? Because if you decide to do it, there's no going back.' = It's not possible to go back.