What Causes Missed Periods And Sore Nipples With Negative UPT?

Hello! My nipples are pointy and hurt. Also my breast are a little bigger than normal. My period is irregular but now he is later more than usual. I had my last period 2 months ago and it wasn t as usually. I took 3 pregnancy tests and they came out negative. Next week I am going to a consultation, but I cannot wait to have a hint about what is going on. Thank you.