Clarke has brought in five players without spending a penny on transfer fees this summer but he feels he needs at least a couple more and is having to leave his business in the hands of chairman Jeremy Peace and technical director Richard Garlick.
The Scot hopes to have Nicolas Anelka back from compassionate leave on Sunday against Swansea but that would only cut his levels of frustration with the strength in depth of his squad a little bit.
"Richard and the chairman are trying as hard as they can to make some deals fall into place," said Clarke. "If we could get business done before Monday, then it would be much better for my state of mind and for my health.
"But it's difficult. When you look around and ask 'Where can we spend our money?', the market is condensed. There are not so many targets.
"It's going to be hard for us at this late stage to pull a rabbit out of the hat. It's going to be a tough few days for us. I'm concerned that we've left it too late and maybe we don't get the right players in to help the squad I've got.
"It's a good squad, but they do need some help. At the moment I can't say I'm confident of landing any player. Time is short, I'm getting a little nervous, but hopefully something will come.
"Rather than for me as a present, it would be a nice gift to the squad I have here.
"My job as head coach is different. I'm not a manager, I don't have a budget, I can't decide who I'm going to go after. The contract of a head coach is such the club has the final say on who comes in and out of the club. It's the same in my case.
"I can make recommendations, but it's down to the club to bring those players in. My job is to train the players I have. Is it frustrating not to have your squad together before the season starts? Yes.
"Is it frustrating to be sitting here now not having made a big-name signing, or a big-cash buy during the summer? Yes.
"But my job is to get over that and make sure the players we do have here go out and give their best for the club. That's what I have to do."