agh my period is driving me nuts!

Every month I got my periods no more than a week late and they lasted 5 days . 
Last month my period was 1month late , I took 2 pregnancy home tests both negative , then got a blood test at the Drs still negative .. I then got them for 4 days
This month I am now overdue again by 12 days! I have got cramping but no period 😓 
I have a small amount of work stress but not a significant amount .
I haven't been on any contraceptive for 7 years 
Any help or advise would be appreciated 😞