Sometimes, a light period or no bleeding at all on the third day could occur due to several reasons not related to pregnancy. Stress, changes in lifestyle, or hormonal changes can be some of the factors. A pregnancy test would be the best way to know if you are worried about being pregnant.

It’s completely normal to feel anxious about this. When you don't get your period after having unprotected sex, it’s usually a cause for concern. Stress, hormonal imbalance, or pregnancy could be delaying it. Also, the fact that you took an emergency contraceptive might mess up your cycle. Just give it some time and you may see your menstrual flow soon. However, if there are other unusual symptoms or the delay persists consider taking a pregnancy test.

The probability of pregnancy from the situation you described was quite low because you took the necessary measures after the unprotected encounter. Although light bleeding might have been caused by the pill's side effects, like irregular bleeding, this is not a sign of pregnancy. This idolizes the truth that hormonal changes can cause such and such. It is common and does not mean you are pregnant. If you're worried, taking a pregnancy test can provide reassurance. 

As per the symptoms listed, an individual is likely to be having irregular periods. This can be attributed to hormonal imbalances, stress, or even weight changes. It is important to consult a gynecologist to establish the cause and then get the right treatment.
 

You may have a hormone imbalance, meaning your hormone levels aren't in the right ratio. This can affect your menstrual cycle, leading to spotting between periods, unusual cervical mucus, and lower abdominal pain. A blood test showing higher LH levels compared to FSH also suggests an imbalance. It's important to see a doctor for a full check-up. They can examine you and discuss treatment options, which may include medication or lifestyle changes to manage the imbalance effectively.

These might be signs and symptoms of other health conditions like endometriosis or pregnancy complications. Consult a gynecologist for thorough diagnosis and treatment.