Sore throat... help!

About two months ago I had an infection in one of my molars. It was a root canal gone bad. The tooth cracked and and a lump formed on my gums. The dentist put me on antibiotics for two weeks and said he would extract it. The antibiotics didn't do a thing. After a week my mouth was hurting and one of my tonsils (the one on the side where the tooth infection was) got inflamed and REALLY sore. So I got a higher dose of antibiotics and the infection was gone in a few days.  Three weeks ago I got a bone graft where the tooth was extracted because there was a lot of bone loss.
I'm not sure if any of this has anything to do with what I've got now, but I thought it might help in figuring out the problem...
Right now my tonsils are swollen and inflamed and they feel just like the one did when my tooth was infected. My neck and head hurt, and my whole body aches. I'm tired, and I feel some nausea and light headed, but not enough to vomit.

Any ideas on what this might be and how I can cure it???