Please please help!! CROOKED SEAM

I am trying to make a double crochet hat. Up to the point I stop increasing my rows my stitch is straight but when I begin to do the part that is just repeated to make the hat longer I gain a stitch every row. :( I am doing ch3 -dbl crochet into the stitch @ the seam as the pattern calls for. Plz help I am so frustrated I want to give up.