Natasha – I can answer your question.
So the cocaine makes the body release a lot of dopamine very quickly thus causing the high. The person using it will typically stay awake, maybe be quite active (mine isn’t anymore but he used to be) like dancing a lot or one of my friends starts doing lots of housework… often users won’t eat because they feel satiated/no hunger… so when it wears off you have someone who is sleep deprived, hungry and has no dopamine… the junk foods can help raise that (especially things like chocolate). Lying in bed is a bit like someone taking to their bed with depression.