Experiencing fatigue and other symptoms, but not long enough for CFS.

[YorkPAMan]

I have been experiencing fatigue, headaches, difficulty falling asleep, and brain fog (most severe symptom) unrelentingly for about 2 months now. My doctor initially suspected hypothyroidism, but my lab results came back fine. He then checked my iron, thyroid antibodies, testosterone, and ran a tTG-IgA. Everything came back normal.

My doctor then suspected it could be depression or anxiety, but I was fine in that regard as well. Other info that may be relevant:

I'm a 24-year-old male. I have previously been diagnosed with IBS-A. I have also suffered from headaches for years. My most recent MRI was 1 year ago, so my doctor did not recommend one now. Behavioral habits: My bedtime routine is incredibly consistent; I limit blue light exposure throughout the day, and I do not consume caffeine. I participate in moderate physical activity.

Does anybody have any idea? I normally never ask for a second opinion, but I'm going crazy without answers.