What is going on?!

Meg • Started ttc 26 may
I usually have short cycles 23-24 days. I'm up to day 28 now and 2 days ago had very light brown discharge. For 2 days it also felt like my uterus is aching(so weird and uncomfortable!!!) tested this morning but bfn :( I don't usually post symptoms, but this has never happened before. 5 months trying now, what do you guys think?