You see a lot of stressed out salespeople out there trying to hit their sales numbers. What they stress about however, is often times things they can't control. You cannot control whether or not a prospect will open their wallet and give you money. Therefore, if you stress over getting a sale, you are stressing over something have no control.
Rather, focus on what you can control which is your behavior. Set a goal each day to execute a set of behaviors that history suggests would lead to solid performance. Then, if you successfully execute all the behaviors you set out to do, feel good that you accoplished your goal regardless if you sold a lot or not. If you consistentely do this every day, you will hit your sales numbers without all the stress.