For bioengineering, I applied to MIT, Berkeley/UCSF, and Caltech. I got invites to MIT and Caltech interviews so far, and nothing from Berkeley/UCSF yet. I know how you feel about going crazy thinking about the consequences of not getting in, but remember that 1 day can change your attitude completely. I was going crazy and losing hope, but then one day, I got 2 invitations, just like that!
I don't know what kind of situation you are in, but getting a job (whatever you might enjoy... for me it's been working at a coffee shop for a few months), volunteering (for local festivals or charities), and investing time in extracurricular activities (sports, choir... whatever you like) could take your mind off of the whole process! Keep yourself busy, think about exciting alternative plans that you could pursue IF you're not admitted. For me, I have a plan to go to France for 9 months to be an English teacher's assistant (there is a program like that for Canadians). This alternative plan gets me excited whenever I think about it, so that the thought of not getting accepted anywhere isn't such a big deal anymore.
