Anyone ever experience this phenomenon? (sort of like deja vu)

So over the past few days I've been having extremely random flashbacks to obscure memories from months or years ago. Like completely insignificant events. And nothing that I've been thinking about or doing has been related to those events as to trigger the memory. For example, earlier today I had a flashback in my mind to a conversation I had with a friend of mine when we were walking to our cars in an Applebee's parking lot like 4 years ago. I didn't even think I still had that memory until today. This has been happening several times a day for the past few days and it's kinda freaking me out. I know for a fact that they're real memories because I had another one tonight about a thread on here from a couple years ago (the worst usernames one that I just bumped) and I remembered every single response. I searched for it and sure enough, there it was with all the responses I had remembered. That's particularly bizarre considering I didn't even post in that thread and likely only read it once. I recall reading somewhere that our brains actually remember everything that we've ever experienced, but it's just a matter of being able to retrieve the information. Seems like there might be some truth to that

And no, I'm not high dammit