Cake effects on the blood sugar

twice now, after having cake and probably estimating the wrong amounts and having too much, i have had imroved blood sugars. once was an hour after i ate it, my blood sugar was normal and later that night it went low. and that day was very stressful. then today, i had a high blood sugar at my snack time and had cake. my blood sugar dropped to normal and i had been sitting around.

this happen to anyone else?