Hunger levels

Okay guys so I'm not pregnant as I am a virgin and you guys have told me I'm not from the stuff I do. But I have a question. So lately like since the start of this year I am getting hungry faster. Like I will have my dinner at twelve o'clock then about three or four hours later I will be hungry again. I used to get hunger five or six hours later. I know I'm probably over analysing this but what could be the cause if I'm not pregnant? My first guess was stress. I am taking my Gcse's this Tuesday coming which is when my first one starts and I am freaking out and am so stressed it's unreal. If you don't know what Gcse's are they are "an examination set especially for secondary-school pupils of about age 16 in England, Wales, and Northern Ireland" this is my only chance to do good. If I fail then it could have drastic effects on my future life. I am desperate to pass. Could this be the reason? I also have IBS if that helps