When you start programming your first web app, you are doing something that you have never done before. You're likely to run into problems that you don't quite know how to solve. This may stress you out!
Stress is not always bad, though. Frustration at any point is a sign that your goals are blocked. Yay--you have goals!! But it doesn't indicate you need to run away from your stress!
According to psychological science, you can view an obstacle as a threat, in which case you might want to flee (avoid it), freeze (stare helplessly at your screen), or fight (maybe say some naughty words).
Or, you could view the obstacle as a challenge, in which case you double down and divert more resources to the problem.
Take a break. Go do something fun. Then when you have more resources to deal with the problem, see it as an opportunity to learn something new. It's a challenge, and those help us grow.