While it could be the card having a problem, it sounds a lot more like you have something on the phone. Virus, malware, bad app or even something that came from the site(s) you were on.
I would consider powering off the phone, do not click on anything that may say to do so, and then start up the phone in "Safe Mode". If the problem doesn't show up in there, then I would clear up the phone. Scan it well for viruses and also malware. Should nothing turn up, then check the system for any apps that got installed without you actually choosing to install them (it happens more than you may think) and if nothing new/unknown, then check any apps you recently installed or were recently updated. You may want to also clear out your browser history, cache, etc., to make sure you don't run into it again.
To get into "Safe Mode" please do the following.
1. First turn off the phone.
2. Next press and hold "Power" until you see the manufacturers logo on the screen, then release the power button.
3. "Quickly" press "Volume Down" and hold it for few seconds until you see the message "Safe mode: ON" or something similar.
4. If you wanted disable it, simply repeat the steps above, and you should see "Safe Mode: OFF" rather than on.