SAT Questions

im really bummed out right out because i got a 1570 out of 2400 on my sat. i’ve been taking practice tests and i get at least 1650 but the real test seemed so much harder for me and i have no idea why. the math concepts were different than the prep tests i took. SATS are really difficult for me for some reason i mean i get good grades with a 3.9 unweighted gpa but the SAT is just a different feel. this is my first time taking it and i am a junior. ALSO if i retake it and do A LOT BETTER do they take the higher score?

im kinda worried at the moment because i want to go to a college such as UCSD UCD UCI which requires high SAT scores and good grades.

i just took the official sat practice test and got a 2140, which is the highest i’ve ever gotten so far. (last time i took was about two months ago and i got a 2020)… so does that mean my score will only go up?? will it ever go down? i feel pretty confident, because my reading and writing scores have been really consistent and my math score just went up 100 to 760… what do you guys think? how reliable are these prep tests?
also are ivy league schools within my reach provided that i have good ec’s, good gpa, essay, recommendation and a higher sat score, since i’m only a rising junior..