Any guesses???

​hi! This is my first time posting on here... I have 3 older children from my first marriage (10,9,7) but this my first time ever ttc. My AF did not show up today... I'm experiencing a lot of symptoms but I took a test on Wednesday and one today and both bfn... Any guesses on what's going on? Was really expecting a bfp this morning :/ is it just too soon to tell since my cycles are so short? Thanks!