It was the second successive game that United had come from behind to steal the spoils and it meant painful viewing for the County manager.
Soon after Iain Vigurs' header just after the break, Johnny Russell latched onto a goalkeeping error to slam in the equaliser before Stuart Armstrong completed the turnaround by tucking in the winner.
"The mistake we made at 1-0 kills us and it was difficult for us after that. We had good chances in the first half," said Adams.
"We got balls in the box and I thought we were the better team in the first half. The mistake we made is a hard thing to take. We've gone 1-0 up and we lost a poor goal.
"Daly and Russell are quality players and they have Armstrong and MacKay Steven coming through. From our point of view we just have to keep going, but we didn't deserve that today."
On Tuesday's tricky clash with St Mirren, Adams added: "We will need to take our chances and stop conceding goals at the back. It will be difficult for us."