Period 10 Days Late... But i have cramps?

Sophie

My period is Ten days late, theres a smallll chance i could be pregnant but its so unlikely that its basiclly impossible, because i was already 7 or 8 days late when i had sex so surely thats not the reason, i've been cramping for a day or two maybe? But my period still isn't here!! I'm not worried as such, just wondering about causes and if/when i should go to the doctors :)