Please help - Might be pregnant

So I usually have absolutely horrible periods, and they didn't used to be regular but I've gotten them pretty on schedule. I've skipped this month and have really bad stomach pains, it almost feels like I'm pmsing but nothing is happening. My stomach is bigger than normal and it's freaking me out, I took a test and it came up negative but the same thing happened to my bestfriend when she was pregnant with her son. I'm freaking out