How??????

I got my first depo shot about a little over a month ago but havent gotten my period it's 4 days late but the doctor said your periods don't skip untill yor second shot and I have pregnacy symptoms. I can't eat anything because I want to vomit it up, I am always tired, my boobs will start to hurt out of no where, my stomach feels funny (like butterflies) , and I have been very emotional. I cry over everything now😦 and I never ever cry!! and my mom , aunt, and grandma keep asking me if I am pregnant! Even my friends assume. What do you guys think?