What are the signs of pregnancy and how can one perceive them differently to period symptoms?

Sore swollen and tendar breast

You'll get mostly the same symptoms as your period. but if you are pregnant, you'll get light spotting or bleeding as this is because the fertilized egg attaches to the uterine lining. the colour of the blood is often lighter, the period is also earlier than your normal period and doesn't last as long.

so the symptoms are tender, swollen breasts, fatigue, slight bleeding or cramping, nausea with or without vomiting, food aversions or cravings, headaches, constipation, mood swings faintness and dizziness, raised body temperature and missing your period.

You did not show us the image of the burger, but i shall try to answer as best i can.  when purchasing food, always consider the ingredients as well as the person who prepared it. consider if they were hygienic people or not, in case the burger was infected with bacteria. no mortal should place an infected burger into their mouth.