Do you think I'm pregnant?

I started cramping really bad on the night of May 5th, and have been feeling queasy and bloated ever since. I have unprotected with my boyfriend, but I take the pill. I miss the pill a lot when we have though, because I am one of those people that is very forgetful. I have had a lot of headaches, light bleeding, brown discharge, and I'm always tired. I have started to feel winded within the past couple days, and I feel like I can't even get up or anything without being really tired. I'm always hot, especially when I first wake up, and I have started peeing and eating a lot more. My period isn't for about a week and a half, but I have taken a couple pregnancy tests beforehand. They both have come out negative, but I'm hoping that possibly my hcg levels aren't detectable yet. Do you think I could possibly be pregnant, or is the pill changing the way I feel? I have taken birth control since I was 16, and I changed birth control pills in December, but the new pill didn't give me any trouble until May 5th. That's why I'm thinking it's not the pill, because it wouldn't cause discomfort 5 months later. Please help me out. I'm so confused. Thank you.