First-half goals from Shaun Harrad and Guillem Bauza had looked set to hand the relegation-threatened Cobblers a first win in 16 games. But Scott Donnelly and Leon Johnson earned the Chairboys a point to keep them third in the npower League Two table.
Waddock said: "It's disappointing because you don't want to be going into the second half trying to chase the game as much as we had to. You can't keep doing that. We didn't perform first half, credit to Northampton for the way they played but we weren't at it at all.
"It was probably a combination of a number of things. You get to this stage of the season and you know what's in front of you, the players probably get a bit nervous but they have to relax.
"It's easy to say but the players have to go out on the pitch and put in a performance - first half they didn't, second half they did.We were 2-0 down last week and we got a point and we were 2-0 down here and we got something out of the game, which is pleasing.
"But we have to perform for the 90 minutes, not just for 45 or 50. We have to turn up in the first second of a game, not the 46th minute. We got something out of nothing really and it's another point."
Source: PA
Source: PA