3 days past expected AF

Hi ladies so I recently had surgery for endometriosis and fibroids. It’s been 2 months and I was suppose to get AF 3 days ago. I got some brown discharge yesterday and really faint pinkish spotting. I feel like AF is coming but nothing happens. I’m kinda bloated but thats it. Im also super regular every 28 days. I’ve never been late ever and I’m 36. I took a pregnancy test on day 1 of when I was supposed to get AF and it was NEG. Now I’m waiting till day 5 to test again. Anyone else go through this?