Late period, negative hcg, recent IUD removal

I had my IUD removed april 8. At the advice of my midwife, we waited until my period resumed which was may 2. I used lh test strips until i had a peak on CD 18. I am now 6 days late on my predicted period and had a dozen negative pregnancy tests. I didn't bbt this month because it's only the first cycle trying for baby #3 but now I wish I had because I'm making myself crazy wondering what my body is doing. I had the IUD since 6 weeks pp with baby 2 so my period never resumed then. Prior to and between kids I always had 28/29 day cycles. So my questions are: is it normal for cycles to be different following IUD removal? Why is my period late if I'm having negative pregnancy tests- i even inverted colors/ contrast colors (not pictured) to help identify a faint line, and nothing. I'm super stressing myself out and making me crazy. (Photos of my cycle calendar, LH test strips, and Hcg strips)