I had issues with my phone so I had to to do a factory reset which made me lose everything. I re-downloaded everything and I'm concerned that my pokemon go account is gone... maybe I am just using the wrong Gmail. Please let me know if it's possible to lose info. I have an s4 android.
You must be using a wrong Gmail. I can confirm you should have no problem, since I did the exact same thing this week. All the data is stored on a server, linked to your google account, so no need to worry about loosing your progress, just try to find out which google account you were using and you will be ready to go.
Your account data is not stored on your device. You can factory reset or buy a new phone and your data won't care. Your account is stored on Niantic's services, regardless of your account type (google, trainer club), so it will be safe.
You just need to remember your account info.
So if your data is gone you just logged in with a different gmail. Just try again with another one.