Me and my boyfriend had a lot of sex last week (we are in a long distance relaitonship) and I had been scatty about taking my pill the week before. I am usually very good about this. This week my period came as normal and was heavy as usual but stopped abrubtly after 3 days where it usually lasts and stops gradually for 5 days. Is there a risk that I've fallen pregnant? I usually take 2 packs of my pill together so I have a period every other month rather than every month but I decided this month to have it monthly. Could this be what's interfering with my cycle rather than pregnancy?

Are you prescribed two pills? They COULD interfere with each other. Unless you are a doctor I would suggest taking exactly what you are prescribed. If you don't like a period every month you can ask your doctor about Seasonique.

If you are having sex there is a risk of pregnancy. You obviously weren't being careful so yes that does increase your risk.