For some silly reason you feel too proud to admit to your friends that you're struggling because even though you're sitting in your pyjamas all day, eating pizza, and crying for no reason other than you want to, are all sure signs of you being totally fine. They're your friends for a reason and they're not going to judge you when you have a slight mental and emotional breakdown. If anything, they'll probably come over to your house in their pyjamas, bring you pizza and cry beside you. People forget how hard a break up can be, both physically and emotionally. Your whole body can hurt and you're exhausted from feeling every single emotion known to man and it's times like these when you need your friends, even if it is to trash talk your ex.
