I am experiencing memory problems (quality: difficulty remembering recent events), fatigue, headache (quality: dull or aching sensation, sensatio...

Persists see MD. Persistent sleep problems could contribute to most of the symptoms. Certainly depression can as well - can contribute to non-restorative sleep. Any medications or supplements recently added or tapered/discontinued? Is there low or low normal blood pressure in your past? Diminished hydration lately? Recent flu, fever, or new medical illness? Any response to home treatments like over OTCs? .
Memory problems. Please see your doc to rule out medical conditions. After than, please see a mental health pro like a clinical psychologist. You may be under stress, fatigued, or leading an unhealthy lifestyle. Peace and good health.