No cardio of any kind? Like
@Devildoc said, hit the pool and also start running. Running is easy to do wherever you are on any given day. Start by jogging places. Going between buildings on campus? Jog instead of walk. Going to the cafeteria? Jog there. Not only will it start to get you used to running if you haven't done any, but it will save time and hopefully make you want to eat more than one plate or one serving.
The workout you listed above... is that once a day or multiple times a day? Are you doing 50 straight of each exercise, or is it 10 five times? How long is the plank?
Additionally, I know we sound like a broken record, but just eat. Don't focus on serving sizes or the like. Someone is handing out cookies? Take some. Add some cheese to the spaghetti or extra meat. Add some garlic bread. Garlic bread is awesome. Try all the ice creams in town. Part of your problem with the workouts may be that you just don't have enough fuel in your system. More fuel, more gains in reps and speed.
Lastly, which of the sites have you looked at thus far? Have you dug around on this site to see what workouts people have posted as doing? The search function is great.
At this point, you don't need to get a specific one for SEALs, Rangers, SWCC, SF, etc... any will do (whichever you can get your hands on and makes the most sense given your availability of equipment). I'm not saying to jump right into one, but look at the exercises they have listed in the plan. Start doing them. Maybe it's only a handful of reps for now. But it's a start to build you up. And stretch. Flexibility will keep you from getting injuries.
My two cents for you based on what you've posted and conveyed thus far.