fatigue can be a reason for memory loss and focus issues, are you getting enough sleep or is there another reason your body might be stressed?
I've had memory loss due to vitamin B12 malabsorption, hypothyroidism, and severe stress. Alzheimer's is also called Diabetes Type 3. A book you might want to read is called Brain Grain by David Perlmutter M.D.
This is a forum for thyroid patients. Do you have reason to believe that your thyroid could be involved? Have you been tested for a possible thyroid issue? If so, please post your thyroid related test results and their refernce ranges shown on the lab report.