Yes it was defenitely not ur day. My advise would be to focus on building confidence along with steady practice. Don't put too much pressure on yourself. Basically don't force the issue. Getting a good score on GMAT requires effort and patience. Since your probably will take the test again:
1. Allow some time to get over ur test experience. Schedule ur test say 4-5 weeks from now
2. Allow some time for concepts to settle into ur mind. Be it Quant or SCs.. CRs/RCs... Go over the concepts several times
3. Work on each of the areas everyday. say a few DS, PS, CR, RC, SCs..
4. Don't hate any section. Develop a liking for each type of question..
5. Practice visualizing urself doing well on the test and scoring a 690+ every day before going to sleep.
"To dream anything that you want to dream, that is the beauty of the human mind. To do anything that you want to do, that is the strength of the human will. To trust yourself, to test your limits, that is the courage to succeed."
- Bernard Edmonds