This is something I am good at.
Energy or not, there are routines you can develop daily. If your doctor gives you the go ahead to walk, swim and do squats, you have a solid routine to count on.
Squats are valuable as an exercising option, because you are lifting your own weight. See you don’t need weights.
Spread out your arms for balance.
Legs should be comfortably apart for a decent squat.
Make sure your back is straight all the way up and all the way down.
Go slowly. Slowness counts. Comfort counts. It does not matter how many you do. Make the squats work comfortably.
Breath properly for each squat.
Someone online moved me with their story about losing weight just by walking. One hour a day, three hours each weekend day helped this individual drop a lot of weight.
I know about lack of energy; I was young in my dark phase. I did not have energy. I did not take medications or do drugs. My brain was different. I Had No Energy–kind of like a big weight in my brain that stopped and slowed everything. I had learning disabilities too.
In my late thirties I got the energy I needed. I took martial arts: Hapkido. They pushed on my back while I was in the Spread Eagle Stretch position so that I could take my nose to the floor, or legs, with my legs spread out. I can not remark on how this changed my energy level, as leg and back pain went away with just this stretch. It took 6 months to get my nose to the floor. But this helped me tolerate strenuous exercise. This may be more information than you are asking for, but this stretch makes a difference.
The number one thing that keeps my energy levels stable: a proper diet with all amino acids, minerals and vitamins from 100 percent whole foods. This means eating a lot of wholesome foods.
Next would be stretching and exercising daily.