1. Nausea or morning sickness: Morning sickness are the nauseating feelings and vomiting you experience during pregnancy. This occurs in approximately 50% to 95% of all pregnant women as early as the first week of pregnancy. Although the name suggests that this is a condition experienced in the morning, it may strike at any time during the day whenever your blood sugar levels get too low.

2. Headaches: If you have never experienced regular headaches before pregnancy, be prepared for some throbbing pain in your head and neck during pregnancy. Changes in your body's hormonal patterns is the primary cause of headaches during pregnancy. Other conditions like lack of sleep, poor posture, stress, dehydration and low blood sugar levels may also worsen of cause headaches.

3. Dizziness and fainting spells: Due to the lowered blood pressure in your body during pregnancy, blood flow to the brain may cause dizziness and fainting spells in serious cases.

4. Mood swings: With your hormones raging, it is common for women to feel cranky during their pregnancy. It takes some time to settle into your new life by adjusting to all the changes in your body and lifestyle.

5. Fatigue: If you feel exhausted and experience some or all of the symptoms mentioned in this article, you have a good chance of being pregnant. Hormonal changes are usually the main cause of fatigue followed by the additional weight you have to carry around.

6. Food cravings: Craving for food that you normally would not eat could be a sign that you are pregnant. Normally, women report cravings for salty and sweet food during pregnancy while others report a peculiar desire for spicy or fatty food.

7. Weight gain and bloating: The combination of your baby's growth and your increased food intake will cause you to put on weight and your clothes to fit tighter than usual. As most women put on weight mainly on their hips and thighs, an mysterious increase in the size of your waist could indicate that you are pregnant.

8. Heartburn: Hormones created during pregnancy may relax the lower esophageal sphincter (LES), which opens the valve to allow stomach acids to flow up into the esophagus causing a burning sensation.

9. Lower back pain: Lower back pain occurs because your growing baby causes your spine to be thrown out of alignment as the additional weight constantly pulls on your back.

10. Constipation: Hormonal changes during pregnancy slows down the movement of food through your digestive system which results in constipation. This could be a sign of pregnancy if you do not experience constipation frequently.

11. Constant urination: Your growing baby in the uterus puts a lot of pressure on your bladder and you may find yourself visiting the loo more frequently than usual.

12. High Basal Body Temperature (BBT): If your BTT stays in the high range for 18 days or more, it is very likely that you are pregnant.

13. Cramping: The growing uterus stretches to accommodate your new baby and this causes menstrual-like cramps to occur.

14. Spotting: Slight bleeding occurs when the fertilized egg begins to implant itself into the uterus any time from 3 to 6 days after fertilization. A lot of women confuse this with their period but this happens usually before the period starts and the discharge is lighter than normal.

15. Darkening of the areolas: Your areolas could darken and increase in diameter during pregnancy. This is a natural process by which your breasts are preparing themselves to produce milk for your baby.

16. Tender or swollen breasts: It is common for women to have sore, tingly, tender or swollen breasts during pregnancy. This feels like a amplified version of how your breast feels before your period.

17. Missed periods: If you have been sexually active and you missed a period, it is a good indication that are you are pregnant. A pregnancy test should be taken to confirm if the missed period is really caused by your pregnancy.

18. Positive pregnancy tests: Pregnancy tests like urine and blood tests are a good way to find out if you are pregnant. However, these tests are not 100% accurate all of the time, therefore you might want to visit a doctor to conduct further tests.

It is possible that you may have some of the symptoms above and not be pregnant. Only a positive pregnancy test and a doctor's examination can prove without a shadow of a doubt that you are pregnant.