I’m a GP and I do think feeling super tired like this is actually way more common than people realise, and partly I think we all just expect way too much of ourselves in modern lifestyles, particularly as women, however I agree that feeling ready for bed at 4-5pm is significant tiredness and more than the average person for sure.
Definitely get your bloods redone, a year was a long time ago, worth asking for an 8am cortisol blood test to rule out Addison’s, check B12 levels and thyroid hormones and yes make sure ferritin is over 50 and not crazy high like in the thousands as per a previous poster with haemochromatosis though this is rare). Maybe ask for rheumatoid factor and ANA testing too (any family history of autoimmune issues like rheumatoid arthritis or lupus? Joint pains?) And a coeliac screen.
If it’s all normal then I would question if you might be depressed or have sleep apnoea (not all people with sleep apnoea snore though many do). It’s more likely if you’re overweight and if the tiredness is “feeling sleepy” sort of tired rather than “too exhausted to function properly but couldn’t necessarily go to sleep right now” feeling. You’re definitely not too young for perimenopause and a trial of topical HRT assuming you have no contraindications might help. And it’s worth really overhauling your lifestyle, do you actually get enough sleep, are you exercising regularly, are you overweight etc. I’d cut out alcohol altogether personally, a lot of people struggle with it around perimenopause.
If all of that is ruled out then maybe it is worth asking for a referral to a chronic fatigue clinic if you have one in your area. Still a diagnosis of exclusion in practice as a pp explained, and definitely a “real thing” (I know some doctors remain sceptical but most doctors my age and younger are convinced) that unfortunately we just don’t have the medical knowledge to treat successfully yet.
I struggle significantly with my energy levels myself, for me I think it is a combination of things, the aftermath of stress from an abusive marriage and draining child custody court battle for many years afterwards, depression as part of bipolar disorder, less than perfect lifestyle especially lack of exercise and just generally being overweight, mild sleep apnoea, chronic degenerative disc back pain, an underactive thyroid and mixed connective tissue disease. I wouldn’t be surprised if I have POTS. Possibly EDS. And actually I also wouldn’t be surprised if I have a degree of fibromyalgia and CFS as well. It’s hard. Weirdly, I have personally found that taking spirulina supplements definitely helps me quite a bit. As do my thyroid tablets and I had to really push to get them prescribed at a time I was technically only “subclinical” for hypothyroidism but literally about to give up work and look genuinely at a life on benefits instead because I just couldn’t keep my eyes open at all or function at all. They made a huge difference immediately and also completely solved at a stroke dreadful muscle aches I was having in my limbs at the time. I can still only work part time due to low energy levels, pain and stress/depression, but at least I can still work. The other thing that helps is regular exercise but it’s a constant tension between my mental and physical health, work, sleep and exercise at the moment!