Ouch, you beat me by 10 ribs. With my 4 broken ribs I started feeling pretty good after 3 weeks and started running again after 4 weeks. It hurt like hell when I started running again but I didn't feel anything moving so I gutted it out.
I suspect that your low energy levels are due to low activity levels. I'd try adding more easy/moderate activity more often (daily if possible) to build a base fitness level before going hard.
All my broken ribs were on the same side and I still had some discomfort laying on that side even a year after the break. Now at a year and a half post accident I still have some achiness when the weather changes but overall feel 100%.
Hope that helps but it's pretty much impossible to compare my level of injury with yours.
EDIT: Have you been checked recently to see if there is still a pneumothorax present?