I think my phone has a virus

Recently, my phone has started to randomly "restart", but it doesn't really restart anything. The screen would glitch, it would shut off, the Apple logo would appear, and, after setting the passcode in again, it would be back to normal.

I also had an instance about a week and a half ago where it would be stuck in a loop of restarting, completely unresponsive. I would hard reset (because just pressing the buttons wouldn't do anything), the logo would appear, it would go to my lock screen like usual (all of the animations were there too), but I wouldn't be able to move anything. I finally got it back after just letting it sit, and it was lagging extremely for about 15 minutes, then went back to normal.

My photos have been resetting as well. I have way too many photos, but in the past, it wouldn't be affected this much. My photos would be "gone", and then slowly come back. Now, my photos are just

Not there

And I know they're still there, because I can take photos and they don't appear in the camera roll, and they still take up the space.

Every time I delete something to make a bit more room, it gets eaten up again like I did nothing. Before they disappeared, I deleted thousands of photos, went to check how much it cleared up, and it didn't clear up anything.

This sounds like a virus to me, but I can't think of an instance except a pop-up ad before this all went down, but I just deleted the tab like normal and went on my merry way. It's happened several times and nothing happened, so I'm not sure that is what caused it.

I'm on an iPhone SE with iOS 9.3.4 (yes, iOS 9. I don't like the new updates. Could that be why my phone is acting odd?)