I like essential oils.. have read that rosemary essential oil on diffuser or usage can increase the memory power.. So, wanted to explore it.. Have used it twice since I brought..Usage had atleast two months of gap between..Have just mixed the drops in the bathing tub and took a bath.. Immediately or a day after, I can clearly notice that my memory power tend to low.. Forget things.. But after a week or so, I don't have that issue and goes back to normal.. This happened every time I used.. Is it normal or issue in usage??