Early period or pregnant ?

I need some advice. I go to the doctors next month on the 9th , but I feel really weird. My menstrual was supposed to come August 17th instead it came August 12 I bleed heavy one day , then the next light , then the next was just a pink discharge , but now I have a brown discharge that I've had for 2 days now and it's going on almost a week. And now I have more cramps and my back is starting to hurt & I see a lil bump in my stomach. And also , my menstruals have been acting up every month. One month it's 34 , next it's 31 , next it 28. & to top it's all off , last night I had a dream I took a pregnancy test and it popped up positive very fast. Can anyone help ?