Where did this growth come from?

Not from rising real consumer incomes.

Not from rising consumer credit.

Not from rising real retail sales.

Not from the housing sector.

Not from a trade surplus.

The growth came from a Bureau of Economic Analysis survey of consumer spending on services. The BEA found that spending on Obamacare drove the US real GDP growth to 5% in the third quarter. http://www.zerohedge.com/news/2014-12-23/here-reason-surge-q3-gdp

In America, unlike in other countries, a huge chunk of medical spending goes to insurance company profits, not to health care. Another big chunk goes to paperwork, which has a variety of purposes such as collecting personal information on patients and combating fraud (probably the paperwork costs more than fraud). Another chunk goes for tests and procedures in order to justify further procedures. For example, if a doctor thinks a patient's diagnosis requires a MRI, he must often first order an x-ray to establish that a cheaper procedure does not suffice.