I would start temping to get in the habit but use a backup form of BC for this cycle.
Annie wife v2.0 to DH and joyfully parenting DSS 20 , DSD 17 , DSD 16 , DSS 14, heart hero DD 4 and DS due 6/2015 . 8/2010
It's common to have longer cycles with delayed ovulation at first when you are postpartum. You just might see a pattern.
How good are you with CM? CM alone is quite effective, and when your temperatures are questionable, it's an excellent way to tell, or it could at least help in interpreting what is going on temp-wise.