The wave itself is body chemistry, carrying you between hope and disappointment, expectation and letdown, and it does not need a reason for any of its movement. This matters, because when you feel low the mind rushes in to explain it, blaming a person, a job, a choice, when often nothing is wrong at all; the wave has simply moved, and tomorrow you will feel different. You are not the wave. Learning to watch it rise and fall without treating either end as the final word is half the work of this authority, and it spares you a great deal of invented drama.
Overriding it usually looks like enthusiasm and feels like certainty. At the peak you say yes to the course, the partnership, the big purchase, and a week later the shine is gone but the commitment remains. In the trough you fire off the resignation or end the conversation, and regret it once the water settles. Spontaneous, in-the-heat decisions are the ones you tend to regret, precisely because they capture one point on the wave and call it the whole truth.
So give every real decision time. The single most powerful thing you can do is sleep on it, and sleep on it again. Revisit the question across a few different moods and notice what stays steady underneath the swings; that quiet steadiness is your clarity arriving. Total certainty is rare for you, so the aim is to become as clear as you reasonably can, then act. When a job offer or a big request lands, say something simple: I want to get this right, give me a few days. Asking people to wait rarely puts them off; done warmly, it often makes you and what you bring feel more valuable, and it protects everyone from the chaos of a decision made mid-wave. Patience is not a delay for you; it is the mechanism by which you find what is true, and every time you honor it, trusting your own timing gets easier.