Hi there. If you were during your fertile days or closer to your ovulation time at the time of your unprotected intercourse, you can expect chances of pregnancy. The symptoms (delayed periods, backpain, abdominal discomfort, fatigue, headaches, nausea, vomiting, elevated basal body temperature) that you describe could suggest pregnancy chances, especially if you are not on any form of birth control method. If pregnancy is suspected, look out for development of any other new symptoms suggestive of pregnancy. If periods have not started within 10 days of expected period dates, or if you have got abnormal periods, or if you suspect chances of pregnancy, consider visiting your doctor/gynecologist at the earliest for thorough examination (to confirm pregnancy related changes/signs in body) and blood/serum HCG level test (to confirm/rule out pregnancy accurately). Be in regular monitoring and follow-up with your treating doctor/gynecologist and report any new/abnormal symptoms immediately. Take adequate rest. Drink plenty of water. Maintain healthy diet.  Take care.