should i be nervous because of my performance?

It doesn't sound like you need to be too nervous, even the fact that you are concerned means you care enough to do well. But, it's also important for you to manage your expectations. There is a difference in getting into the schools you want to go to and getting into a school in general.

You shouldn't feel discouraged from applying to schools you want to go to. But if you are worried you won't get in then I encourage you to do some more research on schools and find some more you think you'd be happy in. Try to find safeties and a few targets.

In terms of approaching your final year, yes, your first semester matters. And your second. Schools are sent your mid-year grades and you are typically accepted into schools under the condition you maintain your current academic standing. It's possible for schools to rescind your acceptance if they feel your performance dropped below their standards. Continue to get good grades, challenge yourself academically, and work hard on your ECs over the summer and fall.

your last year take advanced classes it will make them up and if you still can go to summerschool make up classes! im going to be a senior 2021-2022 with a 2.25 gpa im making up the d's i made and you can retake the SAT!