I'm a student too, and I know how hard it can be to stay on plan when you're so busy and stressed!
I would suggest in terms of motivation to try and go back to one healthy habit at a time. Maybe by eliminating a certain junk food you've gotten into the habit of eating. I think when people get off track they make the mistake of panicking and trying too hard to do everything perfect all at once. Allow yourself to ease back into it
As far as plans, have you looked at blogilates.com? She has some great workouts, challenges, diet plans and its all free! For me, I find exercising outside to be the most rewarding and motivating though(also free) so I go hiking and running on trails near my house or on the weekends will go to some farther away trails.
Good luck! I'm sure by taking it one step at a time and being patient you will be back on plan again in no time!