A large number of new apps that you didn't install could mean that someone else has installed them, either if they had physical access to the phone or know your Google login. But it could also happen if you install a dodgy app with the permission to install others, so if you have installed apps from random websites that's another possibility (if you have ever been tempted by a "free" copy of a paid app then this, or worse, is often part of the price). Or if you have had a system update your carrier could have included a new bunch of bloatware apps as part of the update (in which case it's not a hack or malware problem, just that your carrier thinks it's fine to clutter your phone with crap whether you want it or not).
So, can you uninstall these apps? If you do, do they come back?
And as said above, change your Google password and enable 2-factor authentication if you haven't already done so.