Re: If I had Sarcoidosis would I notice it? (question regarding Vitamin D3 intake)
First off, if you need vitamin D supplementation, it is much wiser--as it is fat soluble therefore stores until needed-- to take the Rx 50k a week pure D3 tiny pill, as studies on osteopenia/porosis and hypo/hypercalcemia show this is, with proper frequent testing after a few weeks and every 3-7 weeks while on it depending on your response predictability/how reliably levels bounce up/down on/off d3... The cost is about the same $8US for 4 at 50k each and only taking weekly or even monthly vs your less effective, filled with more stabilizers/fillers OTC...
As for the sarcoidosis, the TYPE determines the symptoms... You would know if you had the lupus type by the rash on your face. You would notice the most-common-for-females red lumps around your ankles with that type... The serious lung ones you feel... And chest scans give indication of granular lumps, biopsies confirming what is in the lumps; same with the heart.
The type that is hypersensitive with D3 creates a very easy blood marker--despite the relatively low D3 levels you had, your calcium absortion would be high. If the calcium level isn't elevated, then the kind of sarcoidosis that vitamin d--responsible for calcium absorption alongside magnesium and to lesser extents zinc and potassium--plays a role in is not your cause of concern.
You don't mention the things that are really vital--ethnicity/country of ancestry, where you live, what you do for a living... And family history... Sarcoidosis is not often the cause of fatigue, but when it is, usually something is very weird either visually, in breathing or heart stats, or in bloodwork. The rest is a bit like cancer (think the usually painless prostate one here)--it gets regulated before felt or is there til the autopsy at a ripe age like most 86 year old men have prostate cancer that dies with them--an irregularity in cell growth or immune cell response here or there only becomes an issue if the body doesn't kick back into gear or let it lie dormant and harmless as we all have little knots and such.
Has the doc sent you to a rheumatologist about this? If not, the workup for autoimmune AND thyroid (not producing enough estrogen makes for fatigued days, too, if you are female) is a good starting point, then get thee to a specialist; PCPs aren't good at diagnosing endocrine or autoimmune disorders if you do have more than just a D-ficiency...
Good luck and report back!