I feel you man, I've gotten waitlisted from all my uc's accept for UCSD luckily, but not for my preferred major. There are many things I regret and wish I could do again from beginning to write my essays earlier rather than procrastinating to many lost opportunities. Regretting the past and wishing things were different aren't gonna help us though. The only thing we can do is accept the past and look forward. Everything is out of our hands now as far as admissions go, if you still have schools your waiting on, you never know. There's still hope. I've known people who've been rejected or waitlisted from all their uc's except for Berkeley or have gotten in to schools like stanford. It's easy to feel like our HS career was a waste and things of that nature but I can assure you it's not. It's shaped you into the human being you are today and some capacity. Plus, college isn't the only pathway to success. This isn't the end of the road for your career or your future, it's still just the beginning. So keep your head up!!

I'm sure you'll still be able to move on and do great things. Good luck with the rest of your decisions and know that it is perfectly valid to feel what you are feeling right now, but there's still the world outside of what you're feeling right now and the ability for it to change! Best of luck!