Confused, help.

So I took at test 13 dpo and negative (the test I took reads 25 mIU) day 14 dpo no period, later that night started getting back cramps and cramps on ovarys (tail tail sign im gonna get my period) day 15 dpo expected period but awoke to nothing. Took the same brand (25 mIU) test and came out negative. Checked cervix, outer part open and it's hard and low. Now where's my period?