Help!

So I have a ten month old son. I was on the progesterone only bc pull and got pregnant 3 months pp. I had a miscarriage at 18 weeks and after this we decided to start trying. I got a positive pregnancy tests two months later but got my period a few days later so I assumed it was a chemical pregnancy. (This was last month) this month we didn’t really try and only had sexual twice which I didn’t think was during ovulation but then I again I don’t really track other than periods. Anyways my nipples are hurting and so I decided to take a test and I took a clear blue and it was negative and a fr which I got a faint positive. My nipples are so uncomfortable like they were in the past pregnancies but this didn’t happen last month. I’m not sure exactly sure what my cycle is bc i only had one period after my miscarriage before I had the next chemical pregnancy but I think it’s due Friday through Monday somewhere. I know I need to wait and test again but just wanted to here if others have had this happen and why my nipples hurt so bad if Hcg is so low?? Hoping for a better outcome this month