I’m tired of trying and getting no where.

I’m 20 and I’m car sales, constantly wanting to give up due to failure at every turn. The market for car buyers is completely shit right now and no one shows up with a reasonable expectation when shopping. Normally I’d just shrug it off and move on to the next customer, but it’s starting to cost me money and I’m sick and tired of it. When it’s happened 3 or 4 times a day for more than a month it’s really hard to go home with a positive attitude towards anything. How do other people keep themselves motivated in car sales. (I’m also on probation with my dealership for not hitting my required amount last month, so in 3 ish weeks if I don’t hit 7 I’m done) what should I do?