Are we in a tech bubble? Yes, but you shouldn't worry. Tech is always going to be here and it isn't going anywhere the only thing that will change is the feel good aura that surrounds it. Lot's of people come to tech because it's popular not because they like tech.
The talk about a bubble happens when kids sell their apps for millions of dollars. If the bubble breaks you can still your app for tens of thousands to hundred of thousands. Instead of thinking about tech as a make or break industry think of it as an industry with highs and lows. Tech is too entrenched in our society to go anywhere. The only difference is that apps like instagram will not be worth 1 billion dollars it might only be worth a few hundred thousand.