Confused

Valerie • 33 years old. My husband and I have been ttc for 7 1/2 years. November 8th, 2016 I was diagnosed with endometrial cancer. I had a d&c with the Mirena placement afterwords. I received the call November 2017 that my biopsy finally came back cancer free. Feb
Last period was on January 2nd. On January 27th I got a + on my OPK. About two weeks after that I had brown blood one day. A few days later I had a small amount of pink blood just after DH and I BDd. I had symptoms about a week later but didn't think anything about it because I always get symptoms. Today my nipples were getting sore, I wanted to eat everything and was moody (typical pms for me) so I took an OPK and got a + again. I'm just confused about what's going on. Has anyone ever experienced this before?