Head is crooked/squeezing me D:

So this is my first time making a head, im doing a head fro Robbie the Rabbit from silent Hill.
Ive been using the one technique i saw in a Matrices video on how to make a head, starting with a base and ive been building up to make a large base cuz Robbie's head is rather large.
 so while i was making my head everything looked pretty good (pic1) until i put in on my wighead and saw it was reallly messed up (pic 2). My head is almost diamond shaped rather than circular, so it squeezes my head pretty tight whenever i put it on (pic3). my idea for fixing this was to split open the back of my head and space things out (hopefully rounding stuff out in the progress) by taking the margin of space i have running along the top of my head, and continuing it down the back (pic4). anyone else have any ideas?? PLZ HALP TEH N00B

                         pic1                                                                         pic2     


                               pic3                                                                    pic4