The Apple Watch has done well for me. Closing the activity rings gamifies exercise so I actually do it. I caught that you're thin, but to illustrate how much activity that is, I've lost 12lbs in about 4 months. I was skeptical about the Apple Watch but I was reeled in reading that Jim Dalrymple lost 40lbs closing activity rings.

As far as doctors go, your average MD only knows how to traverse a sometimes complicated diagnostic tree and prescribe medication or refer you to a specialist. They look at you and say you don't have a problem.

You might consider seeing a Doctor of Osteopathy (DO). Their discipline focuses on nutrition and on ensuring your body is functioning properly. Which results in treating problems at the source rather than mitigating symptoms. And they can always break out the prescription pad if needed.

My wife has benefited greatly under the care of her osteopath. For example, she had eczema from her fingertips to her shoulders on both arms. Her osteopath put her on the GAPS diet, which cleared it mostly in about a week. To get rid of it completely the doctor put her on the Autoimmune Paleo Protocol. After about a year, she resumed a normal diet and has been fine. An MD would have prescribed steroids on an ongoing basis, likely for the rest of her life. And eventually prescribe more meds to treat the side effects of long term steroid use.

I am not a doctor, but speaking from experience, the one thing you want to be strict about is sleep.

Get plenty of sleep and make sure your sleep routine is mostly the same every day of the week.