...Changes made by suppliers that you don't know about. Something different in your water supply? Food supplier changes?
...Changes in your environment, like painting, furniture, or new people anywhere?
...How's your thinking? Why did you change health care strategies? Any echoes of past experiences coming out? (Unresolved emotions get buried in there, too. Usually these vanish fairly quickly once one recognizes what was REALLY going on, or that this IS just an echo.)
...I suppose a person could ask themselves if there is any large deposit of toxins that takes a long time to dissipate. I might consider this if you are older (over 50)...but less so if you are younger.
Things like heavy metal deposits, or major parasite infections might affect older people.
Getting lots of nutrients from organically-grown foods, particularly things grown on bushes and trees...or 1% solution crystal mineral salts baths, footbaths, or hand baths, could make a lot of difference...or, at least, soothe you.
You could start shopping for, say, a kinesiologist, or anyone well-acquainted with muscle-testing. Try two or three...you'll soon know who you feel best with.
You could also try Bioenergy Therapy with the Domancic Method. I am impressed with it. See the Energy Medicine forum here on CureZone. It can be done by telephone. Very relaxing.
From the changes you describe, I don't think you should be feeling ill at all. I've found that the body rewards us for even small choices for the better.
How severe are your symptoms?
Get a good doctor's opinion if your symptoms are severe in any way. See any specialist recommended. Two heads are always better than one. Then, judge by your own instincts, and the person you are closest to who really understands you. ...That makes a support team of four!
Smile a lot, and laugh, even if there's nothing funny going on, and surround yourself with beautiful things like pictures and music and memories...especially when you are feeling low. Laughter and beauty really help.