Hello fellow senior!
So far for me, it's been very easy-going. Most colleges (if not all) really only care about your performance from freshman year to junior because there's not enough time to look at what you're doing as a senior.
I'm just diverting my energy toward college applications. Although unlike my classmates, I'm applying to about 22 different colleges for a musical theatre major, so my woes will be a bit different than yours, most likely.
But just have fun with your friends and enjoy your time together. I'm really trying to. I go to a really small school and I've been with the same group of 25 people since the 7th grade (about 6 years) and the thought of leaving them for a far off place is heartbreaking. So make memories that last and do what you can to rebuild damaged bridges.
But yeah, chill. Enjoy it and the prospect of college.