help! am I pregnant??

Sierra
My period was supposed to be here on the 25th, it is now July 2nd, and still no real period. However for the past three days, I've lightly bled, mainly a brown rusty color, or sometime a more dirty red. I have also been sick for the past three days which is unusual for me. I've already taken two tests, and they were both negative. I keep thinking I'll get my period, but then it's so light, and stops on and off. Because of the negative tests, I'm wondering if my body is just being weird? Someone please give me advice!