How much can a human brain hold?

has anyone thought about how much stuff our brain can actually hold before it exceeds the limit? Somehow i feel that my brain has just this much capacity, and it is filling up fast. I can feel it saturated with information, and soon, it'll reach a stage where nothing else can go in... It seems that my brain has a small capacity compared to others... I have a feeling that other people's brain can hold as much stuff as they like, but mine just seems unable to do so... Tried studying over the weekends, and i really mean tried very hard, but nothing just seems to get to my brain. Can somebody tell me how i can remember all the stuff i need to remember? and i need to sort this out fast...