If you do get below 80 just remember that depending on the University, you could still get accepted or you could do a bridging course. It's good that you've been studying consistently but remember to aim for 8 hours of sleep.
OP, I'm in a similar situation but I don't take my anger out on others I just keep it inside and feel ashamed of myself. I tell myself in the morning or while I'm at school what I'm going to do in the afternoon regarding studying or assignments but for some reason I just don't do it.
Hey, I do Design and Technology too. I've found these notes and a very good portfolio
Notes:
https://www.dropbox.com/sh/8xid6r9joqcrl41/AADDSbcWNjHjIRxwOBL-WH_2a?dl=0
Portfolio:
https://www.mediafire.com/?ynifvy8tlvdz18q