Help!!!

Hi i need some advice good or bad... ive been off my birth control shot since November of 2014 i was on it for two years its been 7 months of me trying to get pregnant and have had no luck... now this is were i need the help im December i had s normal 6 day cycle and also every month after that on time and always 6 days ive been regular. But just last month i had my period on rhe day i was supposed but only two weeks after that i had another one then again two weeks another and now am on one again they last 4 days and that's it... its making it hard to track ovulation and also im wondering y after 7 months of being regular is this happening can u help me plz im really wanting to have another baby but want to do ot natural no help just me and him. What's going on????