increase in cm and tender breasts...pregnant??

Hi there! I am currently in the 2WW. AF is due in 2 days and i have never had a big increase in cm. might be tmi but i have definitly had an increase in cm and my breasts are VERY tender and sore! i ovulated roughly around the 1st or 2nd of february and BD from the 30th of january until the 6th when my husband left for training for a month(he is in the army) i have taken 3 HPTs and all negative although i may just not have enough HCG in my system...ive done research and all the sites ive read says an increase in cm means a possibility that you are prego...has anyone else been in my situation and had an increase in cm?? also waa slightly nauseous for a few minutes tonight but not for long...dont know if that makes a difference or not...please serious answers! I would LOVE to have my husband come home in a month and be able to tell him im prego!!