My phone keeps restarting multiple times by itself, sometimes not even allowing me to unlock my phone. Usually, after restarting 3 or 4 times in succession, it turns on aeroplane mode by itself. When I turn it off without using my phone, it usually turns off in a minute or two. If I use data straight after turning plane mode off, it will restart immediately. Also, I decided to turn aeroplane mode off while watching a video on instagram, and my phone froze but the video's audio was stuck in a loop, like 'ah-ah-ah-ah-ah', pretty fast.

I don't know if this has anything to do with, but my data usage is currently at 13.6GB. My WiFi does this weird thing where it kicks my phone off, so I sometimes use my mobile data without noticing.

Another thing, I did not download any apps or anything. I'm just at a loss as to what it could be, because it was very sudden.