Breathe. My main advice to you is to just breathe. You'll spend your entire four years worrying about how you're going to finish in time and how much it's going to cost you. Take a moment and sit, take a deep breath, and think about what it all means.
You're doing an amazing thing. You're doing something others strive to do. You may be headed into your fifth year or even sixth, but you're doing it. Watching your friends leave into the real world is hard, but I can tell you I know from experience, don't worry about them. You're doing the same thing, but at your own pace.
When you're sitting there in your room, crying over the stupid rules regarding your graduation application and while you're trying to calculate the amount of debt you'll be in, or even while you think about how many credits equal how many classes, think about this. Think about the years gone by and how fast they went; about the amount of blood, sweat and tears you put into your work. Think about the friends you'll leave behind and the memories that'll fade.
Lastly, think about how amazing it'll feel to walk across that stage and grab that diploma.
In the end, when you look out into the sea of faces watching you as you take that next step, the tears will come. You did it. You're going to do it. Just one more thing; I'm proud of you.
P.S. Your cap is fab.