I'm concerned about medications, side effects, impact on relationship(s)...etc
You are right to be concerned. I have a friend who was so diagnosed. By voluntary committment, he was treated with lithium for several weeks. When stabilized, he was released with a supply of the drugs and instructions. Whether they got the dosage wrong, made the wrong diagnosis, or he simply took too much, or too little, he went into a fit of depression like most of us will never know. In fact, he ended up being involuntarily committed after standing off a sheriff's posse at his ranch.
As a matter of fact, I have never been completely convinced of the diagnosis. Certainly, he was considered something of an oddball, but I don't think he was really outside the normal range of behavior.
Not relevant to the question, but the guy was referred from one doctor to another, and the other turned out to be a psychiatrist, a fact he was not aware of at the time. I have been very cynical about that, and related professions ever since.