The Deloitte Center for Health Solutions recently released results of a nationwide survey of over 600 doctors. While most were happy practicing medicine, many had little optimism for the future.

Some 62 percent of doctors felt many of their colleagues would retire earlier than planned -- especially in the next one-to-three years. 55 percent believe doctors will scale back their hours due to changes in medicine. They did not specify what those changes were.

Some 40 percent of physicians reported they saw take-home pay drop between 2011-12 -- many as much as 10 percent. Of those whose pay dropped, 4 out of 10 pointed to the Affordable Care Act (Obamacare).

Of ALL the doctors in the survey, 48 percent believe their income will drop again this year due to Obamacare. The number of doctors who thought Obamacare was a good idea dropped another 8 percent last year. Many felt uncertainty about changes already happening, or coming soon.

75 percent of the 600-plus physicians in the survey said they felt the best and brightest  students will likely not choose medicine because of the uncertainty and changes in the field. Some anticipated shortages of doctors and nurses. Doctors also felt in the next few years physicians and hospitals will become more integrated. Large health care organizations with numerous physicians will overshadow private practices.

And finally, the number of doctors who gave the U.S. health care system an "A" grade has dropped from 35 percent in  2011 to just 31 percent today.