Having issues with my Pokemon Go App

When I try to log in to my app, the only thing that comes up is my avitar. It is almost as big as the screen on my phone. I was told to un-install the app and then re-install it. If I do that, will I keep all the current data that I have, Pokemon, poke balls, etc…?

If you remember account details you will keep everything
Or try to log out and log in again

You will. No matter what, as long as you know the username and password of your ptc or the password of your Google account you will be fine.