Okay I need advise/help/thoughts???

I've been posting about my symptoms and little things here and there..long story short. I have 31 day cycles. Today af was supposed to show up. I have taken multiple tests and all bfn, even took 1 today and bfn. I've been having cramps and went to the restroom and when I wiped very small spotting and thought "welp, I'm out". Put on a pad and went about my day. Flash forward to a few hours later and I go to the restroom again and there's nothing, not even when I wiped. I have no cramps which is NOT normal if af is here, usually when I start almost immediately I get cramps and heavy flow. I seriously am lost and have no idea what's going on. Any insight, common situations? Greatly appreciated! Could the temp dip be implantation so late? Beyond confused..