Inveting.com - New home sales fell sharply in June, hitting an eight-month low. And sales of existing homes fell in June for the third straight month.Experts say a number of forces are slowing sales.Homebuilders are struggling with the rising cost of building materials and shortages of land and workers, which is limiting new construction.At the same time, the supply of existing homes for sale is historically low.Together, that's caused home values to skyrocket. They recently posted the largest monthly gain since 2006.On top of all that, interest rates are significantly higher than a year ago.Analysts say the housing market is experiencing a vicious circle, wherein rising prices, shrinking supply and higher interest rates are hurting affordability and depressing sales.