I need help ? 5DAYS LATE WITH PERIOD AND NEGATIVE PREGNANCY TEST ?

[Sabanf]

So I'm 5days late today with period , and I've took a test but both tests were negative ?

I've got a 3 year old daughter and I've never experienced a late period ever since I had her , I'm on no birth control pills or injection , what could it be ?

Lower back aches , tender breast and I've got slight cramps lastnight but nothing today ?

I've been getting that nausea feeling aswel ? But it's probably caused due to the anxious about the whole late period anyone that could help me ?

[AllWeNeedIsluv]

Take another test in next few days if still negative and no period go to gp ask for bloods x