Hi there. The diagnosis of rheumatoid arthritis is not purely based on blood tests alone. A negative test simply means your likelihood of developing the disease is likely. Early morning stiffness and involvement of small joint of hands and feet are another important features of this.There is also another spectrum of seronegative arthritis disorders which you might be having so consult a rheumatologist for an evaluation if the problem persists. For mild arthritis the main treatment is analgesics which can be taken on as and when required basis. But you need to get diagnosed early to prevent sequelae of the disorder if any that can lead to deformities of the joints.