You dont tell your age, I think this happens a lot to anyone over 40 , I wouldnt say it means you have alzheimers at all, for a start certain meds can cause
memory loss, even supplemnts have been known to ,other illness like some autoimmune diseases ,if you are concerned ask your Doctor what he thinks. there is a good website ,free, called lumosity google and you will find it, great mind games and exercises to help with memory .Good luck let us know how you are doing .