All I know is I ate way more sugar than usual last night which was otherwise a very normal boring night. And this morning my mood is pretty trash and I'm a bit more anxious than usual. Not a scientific study by any means but there's definitely some correlation for me in the past.
It's likely, that your blood sugar spiked due to the Skittles, your body overreacted, excreted tons of insulin, that crashed your blood sugar and now you're simply hypoglycemic, that is, your blood sugar is too low.