I am relatively new to kegging. I have a beer that I carbonated at 30 psi for 5 days. I would occasionally shake the keg to help dissolve CO2 into beer. This is being carbed at about 62 degrees. After sampling tonight(serving pressure about 5 PSI) The beer tasted flat, but it came out with a lot of foam and alot of sediment. I am wanting to bottle this whole keg off with the beer gun, but this will be my first time using the beer gun. Any suggestions on what is going on and how I would be able to solve it?