Do you cycle more rapidly then? Like several times in a day or so?
I can be up for a few days, then down for a few days or a week or more..
Or sometimes it's within the same day..
Somewhat depending on what I eat or the monthly hormonal cycle.. It can be horrible to only be 'up' 2 weeks in a month.. (or less lol) Or I can write really enthusiastic stuff here and people are all excited, and a few hours later I'm like, 'did I write this?' lol
I'm not really bipolar, as in spending madly (the most went for Amazon) or being totally reckless/promiscuous or such.. I may have some delusions of grandeur sometimes

but then who doesn't?
So I call myself bipolar-ish.. A friend of mine was soo happy when she discovered she was 'manic depressive' lol.. (She was also only -ish, and now has a job, steady guy for years, says he 'stabilized' her a bit..)
I usually don't explain it to people, I try to only interact with them when I'm 'up' or force myself to at least be sort-of 'together'.. It can annoy some people who wonder where I disappeared or something..
I wish my family understood but they're half-suspect of all my other medical conditions already, and for them something 'tangible' like 'I have a cold' is best understood.. So partly I hope the tests would find something physical, partly I fear they would or wouldn't..
They don't really understand about mood swings.. And may also have'em themselves.. My Dad has had mood swings since I was young, he was never treated though and would probably never admit it.. I think he's 'on the border' too.. Not really fully diagnosable, but it can be very annoying.. (He can get hyper etc..) Or maybe it's 'just' ADD/ADHD, those two can be very similar.. Grandma says it'll only get worse as he gets old, she thinks it's onset of Alzheimer's or something... (?)
Look at your relatives, these things are sometimes genetic..
Just you telling things may not be enough, if they read it in the paper or in the church or on TV, or all of those and more, then
maybe they'll understand or agree it's a possibility... It can be exasperating sometimes.. Especially if then (after a few years!) they may start lecturing you about it - about something you've been trying to educate them about all along! /sigh/
So, yeah, I can relate to feeling exasperated.. in many ways.. not just with parents, with society also.. Many people today are on 'happy pills' or painkillers, even if they look like 'ordinary citizens', go to jobs, have kids, etc... It's big pharma making big money, sigh.. When it's the lifestyles and the jobs and systems that would need to be fixed..