Implantation dip?

Yes yes yes I know the “implantation dip” is controversial but I’m just wondering if anyone else has had similar one as mine? The green line is the BFP chart I had for my son last year. The purple is my current cycle (and yes I know I didn’t chart the first half of my cycle blah blah blah I know) I wasn’t planning on checking opk/ temps but I couldn’t help it once I saw EWCM on May 3( had +opk on may 3&4 and L sided cramps on May 5) By this time on my sons cycle I was already getting a super faint BFP. Today I got BFN... any one else have a similar chart with the dip around the same time and got a BFP later? Hope this makes sense! Thanks!