The big-spending Mapgies lost 2-1 to Morecambe, in their battle for promotion.
Campbell said: “It was great to be back playing again and I thought my fitness was pretty good overall.
“It was obviously my first 90 minutes for some time and my first full game with the lads but it felt good, and if we start games like we finished this one we will definitely win more than we lose.”
“Teams will undoubtedly raise their game when they play us this season and we have to make sure we respect that and know that we can’t just turn up and win games,” added Campbell.
“We have a lot of good players in this side but we need to move the ball quicker and if we do that we will be all right.”