Shot in the dark here, but consider L-methylfolate supplements. It’s the methylated form of folic acid. Your symptoms line up extremely well with someone who is suffering from non-methylated folic acid, due to a mutation on the MTHFR gene.

Basically, your body can’t use folic acid as-is. It needs to methylate it with an enzyme (turning it into L-methylfolate) before it becomes biologically available. And there is a gene mutation that causes you to stop producing that enzyme, the same way you become lactose intolerant when you stop producing the enzyme to break down lactose. It usually happens in your late 20’s or early 30’s, so you’re right in expected timeframe for it to happen.

It’s not on most doctors’ radars, and testing folic acid levels on a blood test won’t help, because you probably have plenty of folic acid. Your cells simply can’t access it. So it tends to fly under the radar.

The gene mutation is especially common in people who are AFAB, autistic, or Irish. I know because my wife is all three, and has the mutation. You can buy supplements on Amazon. Most people with the mutation take about 15mg of L-methylfolate per day, but suggest starting with about half that in the morning. It will likely keep you awake (and maybe give you a headache, oddly enough) at first, so start with just taking it in the morning, then once you’re used to it you can take a second one with dinner. Then you can simply move up to taking the full 15mg in the morning.