The Shrimpers were denied a crucial victory when Johnny Mullins cancelled out Kevan Hurst's opener two minutes from time to frustrate Sturrock.
"We had the chances to win the game but we didn't take them," said the Scotsman.
"Four players should all have scored and when you consider that's against a team going for third in the table that's quite encouraging.
"But to concede like we did at the end was disappointing. We should have defended much better and in the end this feels far more like a defeat than a draw.
"We're now six points away from the play-offs but there's still about a quarter of the season to go.
"There are plenty of points to play for and many of the teams still have to play each other so there's everything still to play for.
"However, we really do need to get on a good run."