Implantation? Period? Pregnant? Or what

Brenda

So I'm supposed to start my period on 5/10 but in Sat the 6 I spotted and that was it then Sunday I spotted brown 2x then yesterday I had a regular period I would say (it was kind of heavy) and today really light.. I'm ttc.. I took a test last week and it was BFN and my back has been hurting and my nipps have been so sore

Help!!!