Boss won’t let me use any pto before my two week notice is over. What do I do?

My last day is next Friday and I requested the Monday off of my last week but it was rejected since they are short staffed (their fault) and currently I’m dealing with an extra work load from a coworker who took off all this week which they allowed. Now it’s a problem for my one day and hey tried to guilt trip me and said I used to get sick often but I still have pto so I don’t see a problem here.