An ectopic pregnancy occurs when an egg has been fertilized but is implanted outside of the uterus. Its symptoms can be usually observed between the first 4-12 weeks of pregnancy. Some women might not experience any symptoms at all until the scan at the doctor’s office reveals the situation, or they may have more serious symptoms later.

Some symptoms of an ectopic pregnancy might include

• Late period
• Breast tenderness 
• Positive pregnancy test, sometimes one of the two lines might be pale
• Vaginal bleeding
• Below the norm result for your hCG blood test  
• Feeling sick and/or vomiting with pain
• Sharp abdominal ache
• Pain on one side of your body
• Overall weakness or dizziness or both
• Pain in your shoulder, neck, or rectum

If you have any symptom that could be related to an ectopic pregnancy, seek immediate medical help as this is a life-threatening condition that requires proper examination and treatment. 

Sources:

Ectopic Pregnancy Symptoms and When to Call 911, webmd.com

Ectopic Pregnancy, americanpregnancy.org