The decision to see a doctor often comes down to two questions: how long has this been happening, and is it getting better or worse?
For most colds, minor aches, and low-grade fatigue, a few days of rest, hydration, and observation is reasonable. The signals that suggest you should not wait include fever above 39 degrees Celsius for more than two days, chest pain or breathlessness, sudden severe headache, unexplained weight loss, or any symptom that is getting significantly worse rather than slowly improving.
When in doubt, a brief telehealth call can help you decide without an unnecessary in-person visit.