Left Face, Tooth Severe Pain, Swelling, Migraine. Amoxicillin Given For Tooth Infection. Normal?

I went in to get a root canal on number fifteen tooth two days ago but the dentist wasn't able to finish because he said I had an infection that continued to drain. He gave me some pain medication and amoxicillin. It's been two days and now the left side of my face is in severe pain. I having very bad left temple migraine my left eye, ear, nostril, and throat feel blocked and I have severe pain in my tooth and all the teeth on my upper and lower mouth on lefty side. I have some external swelling but I feel a lot more swollen than I look. My heart also feels like its racing. Is this normal or did the infection get opened and spread. My dentist is closed due to the weekend but I spoke with them and they said if it gets any worse than go to the er and get hooked up to an Iv with antibiotics bc it's dangerous. What could happen if I don't. Am I in danger