Sore Nipples. Am I pregnant?

So I’ve been off the pill since March 2017 and my hubby and I are TTC. I was on the shot prior to the pill and my OB/GYN told me it would take a while to get my periods back. Well during the summer I started brown and dark red spotting all day everyday to the point where I just wore pads all the time. I thought maybe my period would regulate but it still hasn’t. I finally quit bleeding/spotting 4 days ago and all of a sudden my nipples are extremely and unusually sore to where I don’t want to even wear a bra but I have taken an hcg test and it’s negative. Could I be pregnant? I’ve never had this happen before.