The Shrimpers seemed to be heading for defeat until Tomlin's last-gasp equaliser secured a 2-2 draw at Roots Hall.
And Sturrock was thrilled to see the in-form forward grab his ninth goal in nine games.
"Gavin is in great form now and I think we're getting the rewards for sticking with him in attack now," said Sturrock.
"When things weren't going his way and the goals weren't coming his way we stuck by him and told him his place wasn't under threat because all other aspects of his play had been spot on.
"But now he can't stop scoring and it was fantastic to see his latest one go in because I don't think either team deserved to lose this.
"We obviously came from behind to get the point and it does feel more like a victory for us if I'm being honest."