So, this morning I posted a panicked rant (that hopefully few people saw) about a disturbing experience I had after meditating, and the effects I was feeling afterwards, including insomnia, and sensations feeling completely different. I felt uncomfortable all day, and like I wasn't sure I knew my own mind any more. (I later deleted the post after deciding I need more time to make a conclusion about how to feel, which was a wise decision.) I started to feel better later, but just now I tried to sleep and anxiety flooded back, afraid I was going to have the same experience again or that I would be completely unable to fall asleep.

The thing is, when considering what the hell to do I noticed signs that made me think... I'm pretty sure the experience never really happened! Or rather, the sensations did of course, but my interpretation was vastly off, and it was really a result of my overactive mind running away with overconfident beliefs and creating a feedback loop.

After having come to that realisation, my bodily sensations feel completely normal. Or rather, I realise they were completely normal the whole time. I'm pretty sure I couldn't get to sleep because of how worked up I was about what I thought I was experiencing. The 'uncomfortableness' of sensations was me targeting them as the cause of my anxiety.

The strange thing is, I've never been prone to this kind of thing before. I guess that's what happens when I try to sleep right after meditating for over an hour and having obsessively read MCTB for the last four days. Hell, my descriptions of images I saw were practically lifted directly from descriptions from a part of MCTB unrelated to my current state, and somehow I didn't realise that's what was happening.

I'm sure there's a lesson here. I think that the experiences described in MCTB are so wholly unrelated to my current experience of the world as to require me to engage in magical thinking to really believe them (which I'm not usually prone to, but the nature of how MCTB is written makes it obvious that it is largely 'true' to some extent). Believing the book let down my 'reality check barriers' enough for something like this to sneak through. I guess I should stay grounded in my own experience rather than get too caught up in other people's.

Regardless, I think I'll stay away from meditation for a bit until I feel a bit more grounded in reality. On the bright side, meditation didn't ruin my brain and I probably won't be having to check myself in to the ER.

Has anyone else been convinced of experiencing things that they later realised didn't really happen?

I don't think that anything I ever experienced happened exactly the way I remember it. Minds do this all the time. 
and
Staying grounded in our own experience is a good idea. 

I'm glad you noticed how you were projecting your anxieties onto your sensations. That is something we do very often, and it's useful to realize. 

Don't worry, it's normal that meditation messes with your memory. I experienced memory loss much more severe than you did, I even got unconscious several times for up to 3 hours, all this stuff is normal but frightening. I'd suggest not to practice meditation before sleeping if you are a sensative person. 
Just keep it slow on the Vipassana side of things for a while if you feel ungrounded and practice a bit more Shamatha/Metta. 

-O