hi michelle and welcome to pc. everyone has an opinion but after reading your well written history the first thought i had was what helped me. much of my depression came from the past...meaning i hadn't really put those things from the past to rest. i'm wondering if going into something like cognitive behavioral therapy-cbt-would help. i used a phd psychologist, some states don't require a phd, but i figured for my money i wanted to get to the root of the problems i had experienced for so many years and the therapist with a phd had those extra years of schooling. this by no means means that is a sure thing tho. meaning there are good therapists with less schooling, etc., and some phd's aren't always what they're cracked up to be.
i still have things that can "trigger" those old feelings i used to have and use the coping skills i learned in therapy to work through those false beliefs or feelings i had nurtured for so long. it sounds like you've had some prettty upsetting things go on in your life. you may think they have gone away, so to speak, but then something will set it off again.
have you ever tried any form of therapy? my psychol. told me that meds won't just fix it nor just therapy for some people. a combination is what works particularly if the psychiatrist and psychol. converse with each other re the mutual client/patient. it's possible too that you don't really require meds...therapy might work to resolve this. i'm not a pdoc or psyhcho.so i'll just leave these thoughts for you to consider as a means to possibly "fix' these reoccurances of sadness.
hope this helps and we're glad you're here. it's a warm caring community of people and some are in your profession. we come from all walks of life so i'm glad you reached out on the web and found us.
keep us posted on how you're doing, okay?