80% is a good score! Dont kill yourself over it! I did psych 3/4 last year, and i got 88% for my first two sacs (which equates to B+) and i was totally devestated but i ended up with a 40, so i was very happy (honestly expecting 20-25 study score for psych). Your job here now is to put in more hard work for your upcoming sac (you cant change your past but u can change ur future), which is probably gonna be about stress/learning. in order to improve ur mark, i suggest u do as many practice questions relating to stress/learning as soon as possible instead of just reurgitating and memorising content. thats what i did, but after my first sac score, i realised that was not the best way to approach psych, actually any subject. it is always important to understand the content very well and be able to apply it, thats whats going to bump up your scores substantially! Wishing you all the best for psych! It is really a very interesting subject and you will love and prolly do very well in it(except for research methods, which can be pretty boring lol) if u try to engage with the content in a more meaningful and fun way!!!
Hope this helped!!