Avoiding late goals

Here's the chart showing when we score and concede during a game.  Its fairly even through the first 85 minutes but w;ve conceded double in the last 5 minutes plus stoppage time than we;ve scored

Any particular reasons - fitness? tactics?  naivety?  lack of determination? lapse in concentration?

http://stats.football365.co.uk/dom/SCO/teams/Arbroath.html