Thank you all for your replies and words of reassurance.
I understand this forum cannot diagnose based on a single description, I just wanted to know if others have had similar experiences and how the feeling could be relieved.
I couldn't identify any kind of traumatic or stressful event that would have caused the symptoms. Thankfully the feeling began to subside by that night and I woke up feeling normal the next day.
I spoke to my GP and he doesn't believe it was a medication interaction or seizures, but a migraine "postdrome". Excess serotonin due to a medication interaction results in different symptoms to mine. I am to see my neurologist to inform him, just to be safe, in case the experience was a result of seizure activity but it's unlikely.
It felt like I would be like that forever, very unsettling.