Pain in the upper left abdomen. Just below ribs.?

I've had this horrible pain in my "stomach" for going on 3 days now. I've had overall cramps for the past week that, by themselves, have had me in so much pain I couldn't breathe through them. But at 3am Sunday morning (today is Tuesday), this sharp stabbing pain in my left upper abdomen woke me up. It feels almost like those cramps you get when you run (for those of us who are out of shape), but it doesn't go away and it hurts more when I stand up or lay flat. If I stay sitting down, it's not so bad. It worries me though because it's come along with those "flu like symptoms" that doctors are always talking about. I have had a low fever for the same 3 days and yesterday it spiked up to 103.5. I have been able to control the fever so far today with Motrin, but it doesn't touch the abdominal pain. Any ideas what this could be and how urgent it could be? I don't have health insurance so unneeded trips to the ER are a very scary thing for my wallet.

It's beyond my comprehension how you could write Yahoo! Answers with this serious sounding condition. Go to the doctor. Pain, fever . . . your money won't do you know good if you die.