The Moors were unable to follow up their first win of the season and lost to Micky Mellon's side at home, writes Tom Feaheny.
Afterwards speaking to the club's website, McDonald said while he knew it would be a challenge he was disappointed with how they played.
"We knew we would be up against it from the start, I just felt we could have been a bit more competitive in the first-half, we played with nerves in the opening stages and I didn't know why, I told them to enjoy the occasion at half-time.
"The game could have been completely different, we had a good chance at 1-0 and I feel if we score that they are on the ropes."
McDonald revealed the club are closing in on signing another player and would like it confirmed before their next match.
"I would like to think we will get another person in through the ball who is ready for Saturday, that will give us a boost."
They next face Aldershot Town with McDonald saying the games are not getting any easier.
"I think Aldershot will fight til the end and are my outsiders to go up from this league, we know how good they are and that we need a reaction from this defeat."