when??!!

So I have super irregular periods. It ranges from 26-36 days in my cycle. My last period was December 1st through the 8th but on the 15th-19th of December I had a weird mini period. I had just come off birth control on December 8th so it was probably my body regulating but glow said my period was expected Jan 6th and then it changed to Jan 15th. I have not started and other than sore nipples, I have no symptoms of anything. Now glow says I'm supposed to start on Jan 20th? I don't know when to test!!! 😭😭 what do y'all think? Sorry it's so long 😞 super frustrating. With my first, we got pregnant on the first try but I had loads of symptoms..