Dont give up, the fact you have had positive results in the past carries a lot of weight, especially in view of your problems. Bloods can fluctuate. Make sure you get a referral to a rheumie. Keep a note of your symptoms and a record of your blood test results, this can really make a difference.
Hi chin up, labs are not everything. I had my sle done with a biospy and my labs have not shown sle, I even have trouble with it showing infections sometimes. Just remember if it sounds like a duck, it walks like a duck, and acts like a duck, it has to be a duck. Don't give up they will find out what is going on with you.