okay, two solutions to what was problem one or two causes.... if you sewed every row from the same end, it will automatically get wonky (turn into a parallelogram)... easy fix, sew one column from top to bottom and then the next from bottom to top... so tearing apart (if that is how you sewed it) and resewing is quite possible all you need.... you can check by measuring your squares... if they are real close to being even sizes and a good square, then this is all you need...
second solution without taking apart... take a border of 5 or 6 inches (or wider if you need it, depending on how crooked the parallelogram is), make a wedge out of it, cutting diagonally from one corner to the other, rotate one half and put on the bottom, put the other half on the top... now do the same thing again on the sides... you will have a log cabin with wedge shaped borders tilting the entire thing and disguising the 'wonkieness'....
ps...make sure you sew alternate rows and columns from opposite ends in the future...