Now let's get down to bussines, you seem to have a a tension problem with you bridge, this could happend for some reasons, the fist and most probable is that your tremolo has a lose or missing spring (remove the back cover on your guitar and you should find maybe up to 4 springs, maybe one of them is out of hook or missing), the string tension without one spring will be higher than the resistance that the springs should give so the result is that the strings win in the pulling contest.
(Ok all the strat lovers in here give me a hand... how many springs does a regular strat should have??? as far as I remember is 4...) :confused:
Another cause could be heavy gauge strings (maybe from .11 or .12) cuase heavy gauge strings offer more tension to get in standart tune so once again their tension win over the resistance of the springs, the solution would be using lighter gauge strings or tunning low (like drop D or drop C)
So check this things and maybe they are useful, and keep on checking for somebody smarter than me bout this topic.
Rock on and welcome bro...
Power corrupts. Absolute power is kinda neat.