Hormones
Why do i feel different at different times of the month?
Hormone levels rise and fall across the cycle, and energy, mood, motivation and appetite often shift with them. Plenty of people notice a pattern and plenty do not. Either way, a cycle tracker can make a pattern visible if there is one.
What this does and does not tell you
This is general information, not a diagnosis. Only a clinician can examine you, take your history and run tests. The same symptom has different causes in different people.
If something is sudden, severe, or getting worse quickly, get medical advice rather than reading on.