Well, first of all, Lyme doesn't have any "main symptoms" - take a look at any good symptom chart (we have several in the "New to Lyme?" thread) - the symptoms cover all areas of the body -and I for one have had Lyme hit my intestines very hard.
While it's always good to rule out other issues, if your test is positive, then you have Lyme bacteria in your body that will only continue to multiply until treated properly. Remember, Lyme symptoms can come in "waves", where you have periods of feeling fine, but then have times of unexplained symptom onset.
And after just 3 weeks of abx, while you may be feeling fine now, it'll all come back if you don't finish out treatment - this forum and many like it are filled with people who didn't get enough treatment the first time around and their symptoms came roaring back with a vengeance once there was a bit of stress in their lives or for seemingly no reason at all.
And Igenex has provided this for those that wonder about
them:
www.igenex.com/files/QA.pdfwww.igenex.com/Website/#