I don't understand!!

I seriously don't understand why my body does what it does, I'm supposed to get my period today and I'm okay with that but, I have never had nipple pain or swelling in my whole menstration life. It hurts to even brush up against them. And I never had that so I thought for sure this was my month I thought I was pregnant. I've been extreamly tired, back pain, headaches and now the nipple pain, I was excited but now.....I'm spotting and I'm sad!! :'( I feel like I'm never going to have a baby, I've been trying for over a year now. I'm heart broken.