Although sometimes seen in popular diet books or in alternative medicine, "adrenal fatigue" is not a recognized medical term.
Adrenal insufficiency can be diagnosed by blood tests and special stimulation tests that show inadequate levels of adrenal hormones, which is referred to as "Addison's Disease."
Proponents of the adrenal fatigue diagnosis claim "adrenal fatigue" is a mild form of adrenal insufficiency caused by chronic stress. The unproven theory behind adrenal fatigue is that your adrenal glands are unable to keep pace with the demands of perpetual fight-or-flight arousal. As a result, they can't produce quite enough of the hormones you need to feel good.
Existing blood tests aren't sensitive enough to detect such a small decline in adrenal function.
It's frustrating to have persistent symptoms your doctor can't readily explain. But accepting a medically unrecognized diagnosis from an unqualified practitioner (or self-diagnosis) could be worse. Unproven remedies for so-called adrenal fatigue may leave you feeling sicker, while the real cause continues to get worse.
The symptoms that you listed (sensitivity to light, fatigue, asthmatic symptoms, feeling colder) could be a number of different issues like anemia, depression, vitamin B-12 deficiency...or it could be symptoms of something underlying that is more severe like diabetes, hepatitis, hypothyroidism...IMO, I think it is unlikely that it's any of the last 3 I listed, especially because you said that when you changed your bupe regime, the symptoms were somewhat alleviated.
Can you begin to taper off the bupe? Again, IMO - I'd be willing to bet it's the bupe that's causing your symptoms, along with maybe depression? I have no idea, really, as I don't know you and only know the tiny bit you presented in your post.
What I DO know is that you DEFINITELY need to see a doctor, preferably sooner than later. Make sure you present all your symptoms and tell the doctor all the medications you are taking, including the suboxone, AND any supplements (vitamins, adaptogens, etc.) As I said, I suspect (and hope) it is nothing too dramatic, however - the symptoms you listed should not be ignored. As you stated, this combination of symptoms has you describing that they're "holding you back" in life - so GET TO THE DOC.
I don't know where you're from or how your insurance does or doesn't work, but 'round these parts, if I was you and truly suspected that there was some type of hormonal inefficiency or possible CFIDS (chronic fatigue syndrome), I'd ask my general practitioner to please refer me to an Endocrinologist (hormone/gland specialist) and have some blood work done along with presenting your symptoms to rule out some potentially serious issues and eventually focus on what's really wrong.
Good luck!