Help!! Spotting during 2nd week in 2ww

[RKay]

So I've done nothing but drive myself crazy with reading posts. I don't see many current posts anywhere online similar to what I'm going through. Never been pregnant.
This is my 4th IUI and had 1 follicle and good lining. I started taking femara days 3-7 and triggered with Novarel. On my 3rd iui I started spotting brown starting on the 6dpiui throughout my second week and it was unsuccessful. decided to try a 4th and last time and now again I did everything the same and started spotting on the same 6th day again! And still lightly spotting brown.
Has anyone ever experienced this and got a BFP? I took a preg test today at 10dpiui and it was BFN.