wow my mom had placenta previa for me. and i was born 12 weeks early. i highly doubt your "water" broke. and your only 12 weeks pregnant. are you bleeding? what color is it? ive had 2 miscarriages and its hard.
If you think your water broke, yes you should go to the ER. Even if it turns out nothing is wrong, at least you can put your mind to rest. Good lucl to you