thank you all for your input. i'm amazed to see that it's not just mine (or some other random college student's) problem; seems like this demotivational devil keeps on hunting you either until you die or until you kill the sucker. i'm glad to know that i'm not alone but at the same time, i'm sorry for hear that you're stuck on the same boat. thanks to lapid bro for sharing those inspirational words. and thanks to everyone else for sharing those tips on how to get back on track.
i think, as couple of you have suggested, i should start talking/sharing about my achievements with my family members and friends (i hardly do that regardless of how big/small my achievement is). hope that'll help me fuel a bit. i agree with your thought on how family acts as a great motivational source; but sadly - no family here in the States; it's a lonley boring life. but, i try to live as optimistically as possible. to cut things short, seems like these are a few things that are demotivational and are on our way to efficient work/success:
- distraction from online media
- home sickness
- imbalanced physical/mental/emotional health
- lack of friends/fun times

so, here's what i've decided to do:
- build will power and refrain from spending too much time online; if i do i'll do something productive like watching educational documentaries, learning something (like photography as somebody pointed out ^)
- call family/friends often, talk about things going on here and there
-  drag my lazy a$$ back to gym early in the morning, stay cool and avoid stress
- get involved with people, go to events/games,etc
- set a goal for the day regarding studies (make a map on mind what i'll study and how much) and give my best to achieve that goal

for me, thanksgiving break starts as of NOW because I don't have much to do tomorrow. i'm going to put on test these things i outlined ^ and see if that makes any difference (will update at the end of the weekend). i hope this thread has helped/will keep on helping people like me.
Happy Thanksgiving fellas!