It is possible your ping numbers (connection lag) measured too high for an efficient gaming session. If your ping numbers are too high, your device won't keep up with the action, and you'll see your opponents appear to "teleport" around the screen and you may get shot without seeing your opponent (yes, even more than usual). If you're using a VPN, make sure the server you select is as close to Fortnite servers as possible, at least in the same country or region.