TTC with irregular periods

[angelria]

We have been ttc for the past 9 months. With my first child I had difficulty also. The doctors told me I had endometriosis and had to have surgery. 2 weeks after scheduling the surgery I found out I was preggo. After getting my period back from having my first child they have been irregular again. Anywhere from 28-43 days apart. My last period was Aug 22 and when using OPKs I got a positive on Sept 21. Still no sign of AF and a BFN on a dollar tree HPT yesterday (early afternoon). Today is 12 DPO. For those with irregular periods how soon did you get your BFP? I should mention that I am not really having any symptoms other than some minor low back pain on the left that I always get right before AF. I also had some cramping this morning around 3 am that woke me up thinking it was AF and nothing so far. Any ideas?