I'm partial to OB. But I have a Bachelors in Psych too. It truly comes in handy. Especially these days. Not a day goes by that we don't have either a unwed teen mother, or someone who has psychiatric problems (usually mild). For some reason, Rns that I work with are uncomfortable with these patients, so I usually volunteer to these assignments. Now it's not hard core psych, but you still use those skills. Especially listening skills.
And vice-versa, we have OB patients on our psych unit.
Don't pigeon hole yourself. You can have more than 1 passion.