Never got my rootcanal finish and I am afraid it is infected. What can I do?

About 2 weeks ago I went into Aspen dental for fillings. I was tolled that I did need a root canal but we agreed that would wait til the end of the month. When I got there she started to drill the tooth were she wanted to do the root canal saying I just want to see if this tooth can be saved. Next thing I know I was in horrible, horrible, pain. I was yelling and crying my eyes out it was so bad. She would stop for a moment and tell me it needs to be done now, she went back to drilling, it wasn't until the 4th time of me screaming I told her enough stop. She then told me that she already started it and she has to finish it. The pain was horrible. Needless to say she sent me home and didn't finish it after my legs went flying up in the air when I was in pain kicking everything off the table. She put little cotton balls in it and tolled me it can't be pulled after I BEGGED for her to just pull it. Now I am so terrified I am going to have to go though all that pain again I don't want to go back. My tooth is acking me and the little cotton balls that are in there are filled with puss. I keep changing the cotton balls myself at home and I would rather have it pulled. Its in the back anyways. When I called them back to have it pulled once again I am tolled I can't because its considered a "hot tooth" and it has to have a root canal. My tooth is throbbing but its not as bad as it was when she was drilling me to death. I put some oral gell on the outer gums, and rinse it out very well before putting the fresh cotton ball back in. The only prescription they gave me was for Oxy's for the pain and tolled me to take one before I go back to relax me? I thought that was to much. I rather just have it out after all this pain and don't understand why I can't.