Hello,
You describe the symptoms of a badly decayed tooth that has abscessed. You should take an antibiotic by prescription from your 
dentist. I usually prescribe 
amoxicillin to control the inflammation and spread of infection. Patients of record, can ask for a prescription to be called into the pharmacy. You need to be taking the correct dose and at specific time intervals. Anti-inflammatory medication such as 
ibuprofen and 
acetaminophen may reduce symptoms. The anti-
histamine Benadryl is another anti-inflammatory medication to consider. Infections, especially for upper teeth, can affect the sinus cavity and cause drainage. Aggressive infections can create pathways threw bone for drainage. This release of fliud rather than a build up of pressure is most likely why the tooth was not really painful. The fluid is also acidic.
Your tooth is necrotic and does not have a healthy nerve to react, but the spread of the infection has caused drainage. Encourage the area to drain. Rinsing with warm salt water and gently massaging the area is recommended. You must evaluate the tooth for restorability. As long as you have enough healthy tooth structure, you can have a 
root canal, post and replace the crown. The alternative treatment is an extraction. Your periodontal health must be evaluated as well. You must complete treatment for the source of the infection. Infections can spread into your blood system if left untreated. You have an appointment and should have a good, non life threatening, result with your attention to your abscess.
Thank you for your inquiry. I am glad to answer additional questions.