I have ibs and gerd, but since monday i have had a low burning and nausea with a couple occassions of a low grade fever. no d or c just nausea crampin?

Viral?: Neither ibs nor gerd is associated with a fever. But if your symptoms get worse or persist for many days, do consult your doctor. I suspect what you may have is likely a viral infection at your age, pregnancy is always a consideration but there should not be a fever associate with it (if you have indeed measured your temperature and it was >100 degree).