Brown blood is old blood - and this is expelled from the body usually before the start of a new period or at the end of one. It's the body's way of cleaning out, if you like.
Sometimes our period are just like that and it's not due to pregnancy. Only way to know is to take a test.
Brown menstrual blood usually just means old blood. The cramps are probably on about to start once your body gets rid of the old blood.
Yes you could be pregnant. Are you just spotting? If so take a test. When I found out I was pregnant I was spotting. It's not a myth you can still be bleeding and be pregnant. I had spotting for three months once a month like a period before I was told I was pregnant. If you want to sleep, take a test. Easy!! If it is negative, dont worry its just old blood.