Persistent stomach pain after pelvic pain/giardia...

I am a fit 23 y/o female suffering from persistent stomach pain.  It all began after a suspected battle with Giardia (cramping, severe gas, yellowy floating stools, etc...) treated with herbal anti-parasitics.  I have regained my appetite and the weight I lost, but I still have chronic gas, and now a very persistent abdominal pain primarily in the lower left hand area spreading to the upper left hand area.  Occasionally I also experience pain in the lower left hand area, as well as occasionally the entire lower abdomen (which primarily preceeds an exceptional episode of watery stools).  When I press around on my stomach there isn't any sharp pain, but definitely an uncomfortable sensation when I get to the bottom left edge of my rib cage.  

I feel perpetually rumbly, and like I am always about pass gas.  Ocassionally I also get pain in my rectal area which is sometimes relieved by passing wind.  I alternate between bouts of serious diarrhea and constipation with everything in between.  Sometimes one half of a bowel movement will be completely liquid and the other half will be hard and compact...  The bowel movements range in color from very yellowy brown to dark brown, but I have not noticed any blood.  

I live out of the country, and when I need health care I fly back to the states and deal with whatever may be the problem.  A few months ago I had to go back because I was having chronic pelvic cramping for no apparent reason that lasted for close to three months.  There was no official diagnosis made, and each doctor I went to (3 in total) said to wait it out and see if it improved.  Well, it went away, and two days later I had body wracking chills with no fever, then shortly after that the Giardia symptoms began.  (At least the pelvic cramps were gone!) Also, several years ago I was diagnosed with IBS, but have had it generally under control for the duration.

My primary concern right now is that I am slated to return to the US in about a month, and I would like to make sure that I'm not waiting too long to see a doctor.

From what I have read, it sounds like a colon issue, but I was hoping someone else might have experienced something similar or had any ideas....  I am just worried that it might be something more serious and that I am putting myself in jeapordy by waiting to seek advice.  It's not interfereing with my sleeping, eating, or daily function, except to say that my thoughts are consumed with what could be wrong and I worry about it all the time....