Wow, it sounds like time to get a competent dentist!
If you have an abscess or a ulcer, you will also generally have swelling of the area, fever, pain in the general area and headache among other potential symptoms. If you're taking antibiotics, some of the symptoms should begin to abate by the end of the first day. If the dentist does the RC, the abscess/infection will be drained and the pressure removed. You may well still have pain, but the other symptoms should relieve quickly.
You can self medicate with aspirin, ibuprofen or acetaminophen. With all three of these, you want to be cautious not to excess the recommended doses over any given 24 hours. The Dentist should also be willing to scrip you something stronger, Loratab generally being the dental drug of choice.
