I am so confused.. am I too early.

We have been TTC for 2 months now for baby #3. I am fertile, got tubes checked, periods are normal etc. only issue is husband has a "low" count. This month I got HSG and all was good, got 2 iui' during fertile week. Saturday- a whole week before my period I started spotting brownish, it then got heavier but still not the color of my period. Today, I am still spotting lighter and cramping on my left side. I took a test this morning ( 10dpo) and got a BFN.. Was I too early to test? Am I out? Anyone have implantation bleeding that lasted so long?