Hi @Cheryl_C,
I posted about this very thing a little while ago. I was that worried about it I have had two brain MRI's to make sure my brain is functioning. Just waiting on the results of the second one. Unfortunately, the response that I have had from the onc is that's it's not a normal side effect. All you have to do is a quick google to find out that it is a lot more common than they think. There are studies being done overseas on it.
Not one of the side effects you get told about and it majorly impacts your life. Mine was that bad that I set an alarm to remind me that it was my daughters birthday the next day. I was so scared I was going to wake up and have forgotten. i will put an update on my last post as I have been able to alleviate some of it. I'll tag you in it.