You have definitely over-carbed the beer if it was at 30 pounds for more than 2 days. Depending on your particular set up, 7 feet is on the low side. It also depends on how high your tap is from the keg and the temperature. You need to look up how to balance a keg system - line diameter, length, height of the tap, and temperature all come into play.
And once you over-carb, it takes some time to settle down and get it right. I'm fighting a keg like that right now because I forgot to lower the gas (3+ days at 30 pounds).