We need to be sure to listen to the voice in our heads too.
Doctors are not infallible, especially in psych matters (seeing how you can't just x-ray for concrete diagnostics like other kinds of doctors can), and especially if they're trying to diagnose from a snapshot (so to speak) of not having a lot of history to go on, or seeing you over a span of time. Since BP happens in cycles (and therefore over time), short of being acutely manic, it's enormously helpful for them to have one or both of those to work from.

How thoroughly they look, what and how they ask are important for accuracy too. I was first mis-dx'd MDD on that account. Me: severely depressed for months. GP (my first mistake...) "screened" for BP with three words(!) I was such a mess (and didn't know BP) that it all went right over me. BIG clue within 2 days. That went right over her. And I thought it was GREAT (at first), so didn't know to question it. It was a lot of mess till I finally listened to my little voice saying something was very wrong. Bigger mess than ever. Went to P doc, who knew what to ask of the 25 years of evidence I had accrued, and how to rule other dxs out. I've never had a little voice on that. Fits like a glove. Finally knew what I was battling all those years. Got on meds. Man, what a difference.

So yeah, there's nothing wrong with seeking a second opinion especially if something seems off to you. We can be our own best advocates. After all, we're the ones living it. If something seems off, we should listen to that little voice the same way as we would with a physical symptom. Right? It is good to respect doctors' knowledge, not blindly, but tempered with the reality that they are simply humans too, you know?