Every prospect you eventually talk to fits one of two categories — those who have no need for your product or service or those who have just made a purchase from your competitor. The world has surely been knocked off its axis. There's no other explanation.
While staying with it, sticking to your plan and schedule, and forging ahead is usually the best way to break through the blockade, sometimes even that's not going to work.
At those times, take a break!
Find something else to do. Drop in on some customers just to say, "Hello" and find out if there is anything you can do for them. Call three of your biggest competitors and see how much information you can obtain over the phone without revealing who you are. Call on a few companies you're fairly certain have no need for your product or service and see how far you can go.
By focusing your efforts elsewhere for a little while, you give your batteries time to recharge before jumping back into the fray. You also give yourself time to develop a new perspective.
Sometimes you are too close to your work, too tangled in the problems to see what's causing them. You have to step away, step back in order to see where the problem lies. A short break can give you the time and distance to assess your difficulties and ideally address them.