Today started feeling like i can't think clearly, keep saying words wrong, feeling jitteriness, cant concentrate, brain fog. is this delirium?

Delirium?: This is an unusual cluster of symptoms in someone your age. There could be a number of things that cause this. I would be a good idea to see your primary care physician for a physical and evaluation. Some things to consider: medications, Coffee, Smoking, drugs, alcohol, recent surgery, infection, etc. You see there are many things that could cause this. Check with your primary care Doctor.