Psychologists tend to be against medication, or at least against it as a first line treatment for psychological distress. They object to what they call "the medicalization of problems of living." That's how one psychologist put it to me. So your brother-in-law is coming from a natural bias that people with his training tend to have.

If you're new to the option of getting medication for a psych issue, you might find that where a PCP will start is not too different from where a psychiatrist might start, in what either one might initially put you on. All doctors use "decision trees" that kind of tell them what to do when faced with a given set of symptoms. So I would say that starting with your PCP is probably as good a place as any to start.

What would be likely to happen next is that, if you don't improve on what the PCP puts you on, she will refer you to a psychiatrist for at least a consult. That can be a one-time visit for an "expert" opinion. Your PCP has some advantage in that she already knows you.

Bipolar Disorder used to be considered a heavy duty diagnosis that doctors of any type were slow to pin on you. Now the definition of what can constitute bipolar disorder has been expanded and expanded, so that almost anyone can be considered a possible candidate for at least the diagnosis of Bipolar Disorder Type 2.

It's entirely possible that you don't have any true psychiatric disorder, but do have some problems that you are having trouble addressing. That might be how your brother-in-law would want you to initially view your situation.

It's unlikely that medication alone is going to alter your situation all that much. But you never know till you try it.