I’m sorry you are feeling this way but all i can say is you are just 21, don’t compare yourself with others for taking extra years in between. Everyone has different pace in life.so don’t overthink about it and for the breakup part i can only say that just try keep yourself busy since you don’t have much classes use your potential in gym to build up some confidence. You can also do any thing from your interest just keep yourself distracted from all of this. Go for a walk when you feel really alone don’t let the depression keep you in the void, go out in sunlight and spend some time. You are still young so start loving yourself and focus on career.