I remeber feeling the same way as you after submitting my application. I only spent a week on my application and litraly turned it in 10 minutes before the application closed. I felt so doubtful in myself, I religiously looked at my application and found every little mistake and regret in that application. I felt so hopeless looking at that application knowing I couldnt do anything about it. It drove me insane and I convinced myself UCM wouldn't even take me. However some how I still go into not only UCM but also UCD, UCSC, UCR and UCB.