Unfortunately, unless you're filthy rich then changing degree would result in not being eligible for student finance.
The only reason you got accepted for the one you're currently in is because its exempt from the 'equivilant qualification' rule.
On a serious note though, you've done a degree, you've completed a first year of a different subject, do you really know what you want to do with your life?
It sounds like a degree in any other subject would be a mistake for you too.