Every breakup takes both of the partners. Afterwards each one of them can figure out for him/herself how much he/she has been hurt and why, so it is up to you to decide if you can call your ex or not. You are the person who knows you better than anyone else and you are the one who can evaluate if the problems that you couldn’t overcome the first time around are real deal breakers or not.
My observations in such situations made me believe a few things though.