negative pregnancy test but a 18 days late?

Hi,
Welcome to ehealthforum,
Delayed periods, shorter and lighter bleeding, abdominal cramps, lightheadedness, back discomfort, could be few of early symptoms suggestive of pregnancy. The appearance of symptoms suggestive of pregnancy depends on how your body reacts to the changing hormonal status/levels during pregnancy. Look out for development of any other new symptoms if pregnancy is suspected. 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). If pregnancy gets ruled out, further evaluation would be done to look for the underlying cause for the abnormal bleeding that you describe. Treatment as appropriate (based on examination and investigations results) would be started to help you control the bleeding and regulate periods.
If you have been trying for pregnancy (for more than a year) and have not been successful, you should consider getting a complete infertility work-up done for you and your partner to see if there are any underlying causes for the infertility/inability to conceive. Treatment as indicated (based on examination and investigations results) would be started to help you get pregnant. Consider visiting your gynecologist/obstetrician for further evaluation and assistance and be in regular follow-up and monitoring as instructed. Have diet with foods rich in zinc content to ensure better maturation of egg and sperms. Monitor cervical mucus changes and the BBT (basal body temperature) charting to predict your ovulation and time your intercourse for having fruitful results. Have intercourse in positions that allow for deeper penetration for high deposit of semen.
Take care.