Cognition problems or old age?

I have been struggling lately. My bank account has become a major disaster. I used to work as a book keeper and I was pretty good at keeping my own account in check.  Now,  I look at my bank account and cannot even comprehend how to make it balance.  I find myself over drawn all the time.  I can't seem to get the concept of the math anymore.  I seriously need help with my account.  I need to find out if the bank offers help with that.  Maybe I just need to have my husband run my account for me.  It is just overwhelming anymore.  He thinks I am full of it when I tell him that my memory and my brain doesn't work right anymore.  He is always quizzing me on things that happened when I was younger and I can remember that stuff.  Ask me what happened five minutes ago and I couldn't tell ya.  He doesn't seem to grasp that.  I also can't seem to get him to understand that my brain isn't working how it used to.  I am finding work I did last month that doesn't make any sense to me at all.  While my overall health seems fine, it is the brain function or disfunction that is wearing on me now. 
I don't know what I should do.  I feel like a total idiot that I can't even manage my checkbook anymore.  The concept of simple math is out the window.  Numbers just confuse me and make me anxious. 
I was trying to be so positive and today I just want to cry because I can't seem to figure out my finances.