I'm new to the board but I just wanted to offer some kind, encouraging and sympathetic words.
Money is certainly tight when you're a student.(and even after you graduate! lol)
I've only had my GR a week, but have done a lot of research before hand and talked to some other owners before as well. And, I've trained other dogs and parrots. GR's just want to please, that is it. Bentley, he's 2.5 years, doesn't require treats for positive reinforcement...his treat is my hand petting and a hug. I can see in your picture of you and the computer he is your buddy and that's the very beginning step in training completed.
He would do well with some basic training as the others have said.
'get him out of the room in the coridor,first he was moaning ,now he is barking until someone lets him inside.'
That sound like simple separation anxiety.
find what's the best reward for him and keep it close. Have smallll training sessions, 1 minute or so at first.
Sit by him, little treat bite, GOOD BOY!...move a little away..little treat bite GOOD BOY!..move farther...little treat bit tossed to him, GOOD BOY! Stop, then move back over and sit by him and do your homework awhile. Later, repeat it. Don't do too much at once, no hurries. Once he KNOWS you are coming back, it'll help him be more confident in your absence. But, don't stay gone too long or it'll bust the training. Go at HIS pace.
But, here's the hard part: if he doesn't do as you want, he gets nothing, no petting, no treat, in fact, look away from him and be silent. DO NOT SCOLD OR YELL AT A DOG.
That's just a negative reinforce he doesn't understand and in fact may wanna just get loud with you back, like a really bad undeseriable game. If he doesn't cooperate, then move back a little closer and treat/Good BOY! for staying there. Some might encourage sit/stay. That's up to you. Right now, he just needs to know you love him and his best friend has not abandoned him forever. Comfort in your absence.
Once he gets confident that you're not gonna abandon him, and that could take awhile, get a crate and train him to the crate the same manner. little by little.
It's not complicated and Bentley has been VERY responsive to teaching just in one week using those methods. I've taught him to collar/leash/walk/heel/get in the crate/back/in...They're a very smart breed.
I wanted to offer you hope and praise you for your academic pursuits and love of your dog.
Hope this helps,
And as the others have said, EXERCISE..and toys to occupy his busy body and smart mind.