S10 Plus phone-Since yesterday, random ads have been popping up on my screen no matter what I am on-messaging, instagram, youtube, etc. It has to count down to zero before I can hit the x to close it out. Also, there is a black rectangle that appears at the top of my screen after the ad is gone. It makes my screen frozen. I have to hit the back arrow at the bottom of my phone for it to disappear. Does this sound like a virus?