Government Surveillance, Yes..No..?

After all this talk about surveillance and Government control in 1984 I don’t necessarily know what to think if all this government security is something to have a real concern over or if we should just let the government do what it’s got to do.  The obvious positive outcome would be that the government would be able to catch terrorist at a much faster paste. After the 9/11 incident it was discovered that we had several terrorist living among us without us ever detecting a thing. In order to prevent them from sneaking in again we have to take bigger measures. I can see why this would be a real issue since its invading our personal lives and freedom but times are changing and we can’t always stick to our past methods, right? If I’m remembering this correctly there is a clause that can let the congress adjust old laws in order which shall be necessary and proper to protect our people. So in this situation where technology is enhancing every day with new ways to get into touch with people and find more dangerous complex answers, wouldn't that give the government a necessary and proper reason for them to spy and ease drop on us threw technology? I’m not saying they should watch our every single move that we must always be under watch, but enough for them to track what we search up and who we talk to over the internet/phone. When I think of it this way I honestly don’t know what to think and still trying to get some facts straight before I can let out my final opinion. If someone could clear up the whole necessary and proper clause part and if it would really let the government spy us that would be really nice. Thanks!