The worst headache ever...

Okay. I'm not doing so great right now. You may recall how I mentioned that I have had a headache all week? Well, it seems to have only got worse. I don't think I have ever had a headache like this. It's deep in the base of my head and is giving me extreme pressure behind my eyes and pain in my temples. It hasn't felt muscular, yet this morning when I woke up, the entire left side of body is in severe pain and I'm not really able to move that well. So, it feels like it has spread down my neck and into my upper back and chest. I've been taking Panadol (like Tylenol) like candy, tried heat pads, ice, neck rubs, allergy meds and wine (hey, I was a bit desperate!) and NOTHING is helping to ease the pain and it's only getting worse. This seriously sucks. I'm used to headaches and muscle pain, but this is way different. I actually feel dizzy, blurry and nausea with this. AND it's lasted for a full 4 days!!! I'm hoping it's not a reaction to an allergy, like a few people mentioned, because that would just suck. I've never had allergies to things, other than food and I would like to keep it that way! I did start getting the headache around the same time that I got a sore throat, but the sore throat is long gone and the headache isn't. Any thoughts on what this could be? Help!