PLEASE HELP

So to make a long story short my period was due the 7th and it's been on time for the past 6 months. I had sex the 31st-2nd. That's the only time I've had sex in months since I don't see my boyfriend often. I'm currently feeling extreme dizzy and felt that for the past 2 days and I'm having extreme back pain and abdominal pain. I have a 101 fever and am throwing up everything I eat and just feel weak and I'm in a lot of pain. What could be going on? And should I go to the emergency room? I took test that were all negative besides one faint one. My body just haven't felt right and now I'm in extreme pain.