Do I have to put Tag Guard for something as serious as this?
Yeah, Mary-Jo-Wanna does not help. So far, these people are making sense and I would follow their advice. And Ramen Noodles are very staple foods for the cheap. (You get bored of them fast though.)
It sounds like you maybe working too hard on your studies. It doesn't hurt to go for a walk in a park or something to take your mind off something. You can stuff your brain all you want, but if you're not refreshed every once in a while, you're not going to remember anything. It sounds stupid, but flash card facts can really help! I just took a Certification test to get my Network+ and I used flash cards to learn with protocols are connectionless and all kinds of other small tidbits I really needed to remember.
And as much as you need to study, you need to sleep. Make sure you get as close to 8 hours before any tests (yes, I know that's nearly impossible because you are forced to cram, but if you can get up before a test, eat something and study just a little bit to get a refresher, you'll remember so much more instead of thinking just how much the blank side of your test sheet reminds you of a pillow. Also, carbohydrates are much better for the body with little to no sleep compared to more caffeine. Caffeine makes you jittery and hard to concentrate. Carbohydrates are better on the body and makes coming down from lack of sleep much easier.