AF or PG??

So I believe I have irregular periods. For the past 6 months I’ve been using this app and my periods range anywhere from 24-30 days. With that being said, it is almost the end of the month and still no AF! I tested this morning and received a BFN. I haven’t had any of my normal period symptoms and it’s driving me insane!! According to the app I am 13 dpo. I had pelvic pain and nausea around 7dpo which is not normal for me. Do I still have a chance?? Or could AF just be late??