The lower price of oil/gas traded last week will not be reflected for about a month( according to theory) The high prices we see now are the result of trading about a month ago. Other factors impact the price such as supply and demand. This time of the year demand goes up as folks begin to take to the roads, supply goes down,,,price goes up. You can look at all the numbers here and perhaps bust some myths.
http://www.eia.doe.gov/ It may come as a shock to some that OPEC does not supply the majority of our oil.A review of how the commodities market works is also educational.