Now, the first thing to do is - forget it. Take rest for the weekend. Go for movie, spend time with friends, or whatever you like to do (just don't think about the exam and result)
After that, go through your scoresheet and figure out which are the weak areas and try to work on them. Also, once you feel that you are ready, try few mock exams (I found the exam from Sierra-Bates to be one of the toughest).
And most importantly, don't be disappointed. OCPJP exam is not easy one - and that is why it is valued. It is OK to fail, as long as you get learning out of it.
Also, as Seetharaman has mentioned, feel free to post your doubts.
Sorry to hear about that. Your disappointment is natural and ovious. Actually I got a PM from you asking about exam and I asked you if you gave any mock tests but you didn't replied.
Anyway's Let me share you one thing. I also FAILED the exam first time and was in same situation as you. But then I take couple of days off , gather my thoughts and gave it again and second time I cleared it big time and after a month I also cleared OCEJWCD.
So, that was me and I bet there will be many more. So what I am saying is don't let yourself down ,be brave gave some mock exams ,understand everything in Kathy bert book(specially generics and collection as well which you asked me in PM if you can skip some part of it..learn and practice everything).
I am sure that you will gonna clear it next time.