You have already learned about how horrible the plague is, so must I say more? Yes, I must. Well, with Bubonic plague, there is a lot to it. The symptoms of Bubonic plague can occur two to six weeks before you get completely sick. The period in between you get the symptoms and you get sick is called the incubation period.  
The symptoms of Bubonic plague may include:
Abdominal pains
Diarrhea, which may be bloody
Buboes or tender large lymph nodes under arms, neck or groin
Can be 1-10 cm. and occurs in 70% of patients
(The lymph system is a very important part of your immune system.)
Decreased appetite
Tiny broken blood vessels called petechiae
Your skin might also start decaying while you are still alive.
With the Bubonic plague, there is a 4/5 probability that you will die within two weeks.  
If these symptoms are not treated, (and never were), they can lead to Septicemic plague, if the Yersinia pestis gets in your bloodstream. Septicemic plague also occurs when the symptoms of Bubonic plague occur rapidly. It can also lead to Pneumonic plague, if the symptoms develop in your lungs. This happened to 10-20% of people that got the Bubonic plague.  
Yersinia pestis, (the Bubonic Pague bactierium), willl almost never transfer to other people. The only way it will transfer from person to person is if you wear a piece of clothing that was worn before by an infected person. This may happen because if the bacieria is still on the clothing, it could enter through an opening in the skin. However, this is very rare.
When infected with Yersinia pestis, the bacteria multiplies within the lymph system. This is terrible, because your immune system is the system in your body that fights off all harmful bacteria.
Symptoms of Pneumonic plague:
Severe headahce
Rapid heart rate