I think skunkmark's comment is very perceptive, and this may well be the issue at work in your account Essex_boy.
skunkmark's comment also brings up another point worth mentioning:
When you login to your account for the very first time ever, the date range is set to 'yesterday' by default. However, if you change this date range while working in your account, it is a 'sticky' setting. In other words, the next time you login, the date range will default to whatever it was set to when you last worked in the account.
Bottom line: while you are evaluating your stats, it is an excellent idea to take a quick glance at your date range!
I have been 'fooled' by this enough times that I find myself checking it as a matter of routine. Good habit to get into, IMO.