What Causes Vomiting Post Root Canal Treatment?

Hello. I just had dental work done (4 crowns and a bridge) on Dec 23rd. I was in a lot of pain but had been given pain pills for that. Then yesterday morning (Dec 31) I woke up feeling ill around 4am. I laid there hoping to fall back asleep and feel better, but I got up at 8 and ran to the bathroom vomiting. This went on all day and I got a fever and horrible body aches. My brother had just gone to the ER the day before with the same symptoms. I just have been hoping to ride it out but then last night I noticed my upper right cheek was painful to the touch and puffy. It's continued to swell. I was in so much pain from the high fever and body aches that I didn't realize my back molars on the right side were throbbing. I finally got some sleep after being up for over 30 hours from the onset of my symptoms yesterday at 4am and when I woke up a few hours later my fever had finally subsided. Now I'm left with the tooth pain (not as severe as it was while I was with fever) and swelling/bruising under my eye. I have an appointment with my dentist on the 5th, but do I need to go to the ER or can I wait?