Both sides spurned a host of good opportunities as the Somerset side extended their disappointing recent run to five games without a win.
Johnson admitted he is concerned with the Glovers' form - and said only time will tell whether the lost points will prove fatal to Yeovil's play-off hopes.
He said: "It was disappointing because we've drawn at home in an important game. Both teams did their homework and cancelled each other out, and when we needed a bit of a spark we didn't have it.
"It was one of those games which wasn't exciting for the public. We didn't mean it to be like that, but the pitch didn't help.
"Whether it's disastrous we'll have to wait and see. We've got to worry about our form because if our form isn't good, our game in hand doesn't mean anything.
"Players need to work hard to get their form and mental toughness back. We're asking them to bring out their Championship form because, if we do go up, they'll need to be at that level.
"The boys know we're disappointed but we'll see if it makes a big difference later in the season.
"I wasn't happy with our set plays. Our delivery was poor and our centre halves need to be a bit meaner in the opposition box.
"It will be touch and go whether Jamie McAllister will be available for Monday, so we'll see over the weekend and see how he performs in training."
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