I need help now

Hey I cant recall wether or not an over heating problem existed prior to this, but, my problem started when I was riding down the street, suddenly heard a pop and observed that it was fluid leaking everywhere, in which it was anti freeze.(Sorry the cars a 2000 ford focus). The radiator hose on the lower passenger side was busted, so I replaced it with new hose and braces, refilled it with radiator fluid and after driving it a day or two this overheating problem occurs. After questioning several affordable neighbor hood mechanic it was told that it simply needed a thermostat.I also had that replaced and now the overheating problem has continued and from my observation seems to be worst(reaching red within a 1 to 2 mile distance. Took it back to the mechanic that replaced the thermostat and he said the hose was not placed all the way on. But im thinking if the hose wasnt on then why is pressure building in the hose? Pressure must not be circulatin if there is obvious pressure could someone please help