Does Continued Spotting, Pain In Head And Back With Nausea Mean Pregnancy?

my period was 3 day late and i usually have a 28 days cycle and its like clock work every month, anyway my period came on the 4th day and was lighter for a day then got a lil heavier then just spotting for 2 more days but what i find strange is that i am still having the same backaches i usually get a few days before and the first 2 days of my period but never after my period and its like a dull aches which gets worst through out the day especially when i'm lying down or sitting and its off and on all day and i keep feeling nausea for the by 10 days and i was getting lots of headaches even though i drink 2 litres of water everyday and i haven't slept well for the past week. I took a pregnancy test when i was a day late it came back negative today is 8 days since i started my period and i still have all the same symptoms so is the a chance i could be pregnant?