Please HELP! Period problems!!

So I’ve been on birth control pills for 3-4 years now and have never had problems with it. In February 2019 though, I accidentally missed pills and got pregnant. Miscarried in March 2019 at around 6 weeks but until all of that I had a viable pregnancy while still having a normal period. Anyway, I have been very careful to take my pill everyday since then and haven’t missed one. The pills I’m on are a 28 day cycle with the placebo in the 4th week for my period. The placebos start on a Sunday so I normally don’t start my period until midweek. Well last cycle, my placebo started on Sunday September 29th, and I got my period that day (but what is weird is that I don’t take my pills until night time before bed so i started my period on the day of the placebo before even taking the placebo) like I said about a previous pregnancy, I was still having a normal period then so now I can’t even trust my period to be right. Today is Tuesday October 29th and I’m on my placebo pill week again (it started Sunday the 27th) and last night (after intercourse) I went to the bathroom and thought I had started my period (brown blood but that’s how it always starts for me) I put in a tampon and went to bed. Woke up this morning and took the tampon out and not a speck of anything was on it. I figured it could have been from laying still sleeping all night or maybe sex and I didn’t want it to surprise me today so I put another tampon in just in case. I only left it in for maybe 2 hours but nothing was on it and it was super dry. What’s going on? Could I be pregnant?? Is this happening again? Ugh omg I’m so confused PLEASE help me!