dizzy spells, headaches, and have been light headed.

Hi,
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If you have had unprotected intercourse after last periods (closer to ovulation time), without protection, then the current symptoms of delayed periods, sensitive nipples, mild abdominal cramps, dizziness, headaches, lightheadedness, constipation, etc could suggest chances of pregnancy. Look out for development of any other new symptoms if pregnancy is suspected. If periods do not start within 10 days of expected period dates, or if you get 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). Urine pregnancy test kits usually start showing positive results after about 20 days post-conception (roughly corresponding to about 1 week after your missed/altered periods). You may also consider taking a repeat urine pregnancy test (on an early morning first urine sample) after 7-10 days of missed/altered periods to see if you get positive results, or get it confirmed by a blood HCG test. Be in regular monitoring and follow-up with your treating doctor/gynecologist and report any new/abnormal symptoms immediately. Drink plenty of water. Take adequate rest. Maintain healthy diet.
Take care.