Your symptoms do sound a lot like Lyme disease. I had very similar symptoms late last summer though not quite as bad--dizzy, ringing in the ears, nauseous, difficulty breathing, heart pounding, fatigued and generally crappy feeling. The dizzyness never got so bad that I threw up though. I was thinking Lyme disease at first also, but it normally comes along with a characteristic rash.
After much poking and prodding (and $$$) and the suggestion by the Dr. that I might have a brain tumor (and my ensuing freaking out), it turns out my problem was simply allergies. This time of year is terrible for hay fever. But one treatment with a nasal steroid and most of the symptoms went away--even though I've been taking an oral antihastimine for 25 years.
Though it's possible, I'm not saying you've definitively got allergy issues. My point is your diagnosis may very well be something you were not expecting--and it is much more likely than not that it will be something relatively simple and easily treated. So take it easy and try not to worry too much about it.
Oh, and I hope you feel better soon.