Extreme fatigue/lack of energy and motivation without Adderall?

Hello all! I am new to this subreddit and needing advice. I was diagnosed with major depressive disorder about 10 years ago. I started taking Lexapro in 2013. It worked great for several years but then it kind of stopped working so my doctor put me on Cymbalta instead in 2018/2019. I’ve also been taking Adderall on and off since 2014/2015; I asked my psychiatrist to try Adderall due to extreme fatigue that made me unable to focus on anything else other than how tired I was.

When I first started taking it, I felt amazing. However, sometimes it seemed to lose its effectiveness so I’ve tried other medications like Ritalin and Mydayis over the years but I always end up coming back to Adderall because it works the best for me.

I’m currently taking 50 mg daily “as needed”. At first, I didn’t need it everyday but it has gotten to the point where without it, I will literally sleep for 18 hours straight. I honestly doubt I would get anything done if it wasn’t for Adderall. Without it, I have no motivation or energy and I am exhausted all the time for no reason I can think of.

But aside from the fatigue, my depression is fine. My mood is great and I’m pretty happy. I think that lack of motivation comes from the exhaustion.

I just checked my cortisol levels and they are fine. I have a thyroid problem but it is currently stable with the use of medication and I’m under the care of a physician. I get labs done regularly and the results haven’t noted any deficiencies. I did have a sleep study a few years ago and they said that I didn’t have sleep apnea or anything like that but I also didn’t go into REM sleep but my psychiatrist said that is a side effect of almost every antidepressant. We’ve also tried to supplement the Cymbalta with Wellbutrin but that didn’t work either.

So Adderall has also kind of become a way to combat the fatigue from not getting any REM sleep as a result of the antidepressants; it’s just a viscous cycle. Recently, the Adderall seems to not be working as well. Normally, I take it and I’m good for 12-14 hours but lately after about 8 hours, I’m exhausted and need a nap. Anyone else know what could be causing the fatigue or what I can do to help it besides using adderall?