I had 5 fillings done last week, Monday they did 3, The following day (Tuesday morning) they finished off and did the last 2 fillings. Within a couple of days I had terrible nausea and a migraine along with it. By Friday I had a sore in my mouth that hurt like no other and swollen gland in the side of my neck, I could barely eat. Saturday morning I rinsed my mouth out with listerine and I was okay... for only a couple of hours. It was sore, and eventually by Sunday I had several sores. On the outside of my lip like barely halfway between the opening of my mouth. And on the roof of my mouth, sides of my tongue, my gums are swollen and red, I can't brush or they'll bleed bad. I can't eat because they're so sensitvie and the cold sores hurt as well. I don't know what's up with me, I went to the dr Monday and she prescribed 4 different medicines but they don't seem to be helping at all... and orajel doesn't work. It only lasts for about 10 minutes.

Go back to the dentist and let him/her see your mouth. You could possibly have picked up a virus during your treatment. You might want to ask for a tour of the sterilization area of the office and ask what protocol they follow.
You could rinse with 5 drops of tea tree oil and water to help with the sores.
You could definitely have some tooth sensitivity after having so many fillings done. If you have a filling that feels high you need to have the dentist adjust the bite. It could take 2-3 weeks for all of the sensitivity to go away.