Gaslighting was largely an obscure or esoteric term until the mid-2010s, when it broadly seeped into English lexicon.
One way to get around this is recording everything you do and feel on a daily basis. Otherwise it's one claim against the other.
Historically, it's similar to the way women try to control men since they're not as physically competitive - if you've seen chinese dramas featuring an emperor and his wives it always boils down the cliche of 'oh but it's for you, the emperor's sake' or something like that.
https://www.salon.com/2016/10/16/donald-trump-as-a-gaslighte...
My best guess is that it has come up as part of the Amber Heard / Johnny Depp trial and that has spurred a lot of people searching for it.
[1] Past 5 years, March & earlier - https://trends.google.com/trends/explore?date=2017-03-01%202...
[2] Past 90 days including giant spike - https://trends.google.com/trends/explore?date=today%203-m&ge... (if you go to past year you can see the spike)
My personal guess is that it has to do with psychology and mental health awareness going mainstream due to social media and psychology channels on YouTube.
https://trends.google.com/trends/explore?date=all&geo=US&q=g...
That's not to take way from your experience or suggest it's not the appropriate word, I'm quite sure it is. I'm just curious if I was really oblivious of concept before my own exposure to it, or if it was called something else?