Am I experiencing ectopic pregnancy or normal period changes?

You don't need to stress about nipple discharge during pre­gnancy - it's a natural thing called colostrum, this whitish fluid is your body's way to nourish the baby soon. If its bothering too much, use mild soap and water to clean the area ge­ntly. But watch for redness, swelling or discomfort - as it warrants medical attention.

Irregular or abnormal menstrual bleeding can occur due to many reason like hormonal imbalances, stress, changes in contraceptive methods, etc. It doesn't always mean that its about pregnancy. If you are concerned about the possibility of pregnancy, it's advisable to take a pregnancy test to get a clearer understanding of your situation. 

It's important to prioritize the health and safety first and so i recommend you to consult your gynec for your particular case. 

Based on what you've told me, the chances of you being pregnant are slim. The emergency contraceptive pill is effective if taken shortly after unprotected sex. Women can experience nausea and abdominal discomfort as side effects of the pill, which do not necessarily imply that they are pregnant.

After sex, it usually takes 1-2 weeks to tell if you’re pregnant but sometimes there are signs like nausea, tiredness, or changes in appetite which occur when a fertilized egg attaches itself to the wall of the womb. To make sure though, take a home pregnancy test; it’s easy and will give you an answer.

It is impossible to know whether the bleeding occurred because of premenstrual spotting or implantation blood without a physical examination. To get a clear idea, plz visist a gynecologist