Going crazy!!!

So apparently, my body (especially my boobs) thinks that I'm pregnant, even if the tests don't think so! I'm at CD42, and I got a positive opk 18 days ago... All tests have been negative but I'm having a ton of symptoms...my boobs and nipples are super sensitive and feel bigger. I also have blue veins and I noticed that my areolas are quite a bit darker. That didn't even happen the only other time I've been pregnant (when I miscarried in October at 7 weeks). I've also been moderately dizzy, nauseous (but no vomiting) and I've been getting headaches every day. I just wish I knew for sure...